Studio 1558 drivers for Windows 10

As I mentioned in some other recent blog entries, I recently installed Windows 10 (x64) on my Studio 1558 computers. Note that this was a clean install on a formatted drive – if you do an in-place upgrade from an earlier version of Windows, things may behave differently.

Windows 10 (LTSC 1809 in my case) installed without any difficulty, but even after installing all of the Microsoft updates, some device drivers were still missing. As Dell never officially supported anything newer than Windows 7 on the Studio 1558, it isn’t a simple case of going to the Dell support page for the 1558 and downloading drivers. Some older drivers will install correctly, some will complain that they are for a different Windows version or will install but give errors when used. I have collected the device drivers needed to clear all of the “Unknown device” errors that show up in Device Manager. The system could possibly benefit from additional drivers such as the Intel chipset driver, but it functions perfectly without them. You may not need all of these devices – my 1558 has just about every option imaginable.

The drivers you may need are:

  • Wireless 365 Bluetooth module driver (says it is for the Wireless 380 module, works with the Wireless 365)
  • ST Microelectronics Free Fall Data Protection driver
  • Ricoh Card Reader R5C833, R5U230 driver
  • Dell QuickSet application
  • DW5808 LTE Mobile Broadband and GNSS driver
  • DW5808 GPS Rollover fix
  • DW5620 Mobile Broadband driver
  • Verizon Access Manager (VZAM) for DW5600 and DW5620 application (not needed for DW5808 card)

I am listing Verizon Access Manager for the DW5620 even though it is not strictly required – after installing the DW5620 Mobile Broadband driver, the cellular modem will show up as a usable device in Windows 10. However, if you rely on the native Windows support you won’t have access to the usage data that VZAM provides and as I mentioned in my post about the newer DW5808 module, Windows 10 has no native SMS support. The Mobile Broadband SMS Toolkit mentioned in that post works with the DW5620 as well, so you can use it to send and receive text messages.

I have installed each of these drivers on my Studio 1558 and they all work properly under Windows 10 x64. It is extremely unlikely that you are running the 32-bit (x86) version of Windows 10, since you’d be limited to under 4GB of RAM which will make the system pretty unusable – install the 64-bit (x64) version, even if you only have 4GB of RAM installed. Note that you can upgrade the Studio 1558 to a maximum of 16GB as I describe here.

I have verified that each of these files is downloadable as of March 2nd, 2021 via the link I’ve given. Vendors may re-organize their web sites, so if you are reading this at some point in the future, those links may not work. I have mirrored each of these drivers (with additional information in the filename so you can see what the file applies to) here. If at all possible, you should use the official vendor downloads and not the ones here since you don’t know if my files have been tampered with or not. I have verified the MD5 checksum (when available from the vendor site) with each of the files in my mirror.

DW5808 Mobile Broadband on the Studio 1558

I have been running DW5620 mobile broadband (cellular data) cards in my Studio 1558 notebook computers for many years. This is a 3G / EVDO card that will fall back to 1xRTT if a 3G network is unavailable. Although I have these cards activated on Verizon, they are no longer activating new 3G devices on their network – 4G is required at a minimum. This is so the existing population of 3G and older devices can “age out” and Verizon can re-use those frequencies for 4G and newer service instead, per this article in The Register. That article also says they intended to shut down their 3G network on December 30, 2020 although it appears to have been postponed for an unknown amount of time. The article also quotes a Verizon spokesperson as saying “Yes, our 3G network is still live today. We’re actively working with customers to migrate them to new technology. It’s not accurate to say the network will remain active ‘for some time.’ While we want to make sure we care for our customers – both consumer and IoT – our plan is to move them ASAP and retire the 3G network.” In any event, the writing was on the wall and it was time to upgrade the mobile broadband card in my Studio 1558.

I decided that as part of my Studio 1558 re-evaluation, 16 GB memory upgrade and Windows 10 install, that I would also upgrade the mobile broadband card to the latest possible. That is more difficult than it sounds because the newer cards are generally M.2 instead of the Mini PCIe form factor found in the 1558. The newest card I’ve found is the DW5808 (not the DW5808e) which is a Dell-branded Sierra Wireless MC7355 (PDF specification). That is a card that according to the datasheet supports LTE, HSPA+, GSM/GPRS/EDGE, EV-DO Rev A and 1xRTT. It is supported by all major US cellular providers, although I have only used it extensively with Verizon. I did test an AT&T SIM and it allowed me to connect to AT&T’s “sign up for mobile broadband service” page.

When purchasing one of these cards, it is preferable to purchase a new one as that guarantees it has never been blacklisted for being on an account that has an unpaid balance with a provider. A new card should also come with a manual and a full set of stickers. The stickers include the IMEI (taped to the top of the module) which is applied next to the SIM slot in the battery compartment, an FCC sticker (to be applied in the matching location on the inside of the 1558’s removable bottom access cover) and a Dell part number sticker (also for the inside of the cover). Here is a picture of what you should get, courtesy of eBay seller pcs_jec:

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If you already have a mobile broadband card in your Studio 1558, you can simply replace it with the DW5808. Note that the antenna connections on the DW5808 are reversed compared to the DW5620, so be sure to re-connect the antennas in the proper locations. The center antenna connector is not used in this application. If you do not already have a mobile broadband card installed in your 1558, make sure that your system (primarily the lid) supports it and has the appropriate antenna connectors. You can refer to my blog post “Dell Studio 155x Wireless / Networking Options” here for more information. Here is the antenna connector layout from the Sierra Wireless “Product Technical Specification”:

Unlike the older DW5620 cards, a SIM is needed for service – if you don’t have one installed, trying to connect to mobile broadband will display the message “Insert SIM”. The advantage of this method is that you can just move the SIM card from computer to computer without needing to talk to your cellular provider about changing devices. One downside to the SIM location (in the battery compartment) in the 1558 is that it is a bit tricky to remove the SIM once it is inserted. Make sure to observe the correct orientation when inserting the SIM (there is a molded image of the correct orientation next to the SIM slot in the battery compartment). This picture shows the full-size SIM inserted in the SIM slot with the orientation matching what is molded into the case above the slot, in the center of the picture. You can also see the location for the IMEI sticker:

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You will need the appropriate driver for your operating system. For Windows 10, that is “DW5808E and DW5808 LTE Mobile Broadband and GNSS Driver” from here. Windows 10 has built-in support for mobile broadband, but the Dell driver is still needed. Older versions of Windows needed an additional application to handle mobile broadband – for example, on Windows 7 with the DW5808 card, the “Connection Manager Application for DW5808/5808e/5809e/5570” application is required. On older cards like the DW5620 the application is usually provided by the cellular carrier. For example, VZAccess Manager (VZAM).

The one thing all of these applications have in common is that they are (for lack of a better word) “twitchy”. VZAM on the DW5620 would frequently report “card not detected” or fail to power the card on or off. The only corrective action at that point is to reboot and possibly power cycle the computer. I’ve run into this on multiple Dell and HP notebooks, even with factory-installed mobile broadband. Unfortunately, this behavior continues with the DW5808, at least in the Studio 1558. To be fair, neither Dell nor Sierra Wireless ever implied that this combination was tested by them. In my testing, either the board is detected at startup or it isn’t. If it isn’t, a reboot will fix it. Not really any different than the older DW5620 with VZAM. In further testing, this seems to be related to not having a SIM installed in the computer – I suspect the card is “bootlooping” trying to recover from a “no SIM” condition. All of the 1558/DW5808 systems I have that include SIMs behave properly – it is only the ones without SIMs that misbehave.

Like the DW5620, the DW5808 includes GPS functionality. Unlike the DW5620, the DW5808 does not make that functionality available as a COM port by default. A registry modification is needed. That is only for advanced users, but if you’ve gotten this far I think you qualify. The particular key is in HKLM > SOFTWARE > Sierra Wireless > QDL and you need to change the USBCOMP value from 9 to 8. The underlying reason is rather complex, but if you want more information I’d suggest starting here. As you can see from this screenshot, after changing the USBCOMP setting the DW5808 appears as a modem, as a network adapter and as 2 USB serial ports. DM is Device Management and NMEA is GPS:

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The DW5808 and many other cards from the same era suffer from the “GPS Rollover” problem which causes the date to be reported incorrectly after November 3rd, 2019. As Sierra Wireless describes it, “The Global Positioning System provides positioning fixes and timing information to GPS receivers (such as MC73xx, EM73xx, WP75xx and WP85xx modules). The timing information includes a ‘week’ component represented as an integer value from 0–1023. This value will ‘roll over’ on 03 November 2019. As a result, the time reported to customer applications by MC73xx, EM73xx, WP75xx and WP85xx modules will be incorrect. (Note: Positioning fixes will not be affected.)” Since Windows uses the Windows Time Service and not GPS for setting the computer’s time, this is likely a non-issue for most users. However, Dell does provide a fix if you need it. Note that despite being described as “Application”, it is the one-time rollover fix and does not permanently install any software on your computer.

The Dell DW5808 Windows 10 driver installation also adds some Bluetooth device drivers, despite the DW5508 not including any Bluetooth hardware. This may be because the driver supports multiple card models. There is no Bluetooth hardware in the DW5808, so if you need Bluetooth support you’ll still need the Dell Wireless 365 Bluetooth adapter.

There doesn’t seem to be a native way to send or receive text or multimedia messages (SMS/MMS) in Windows 10. Microsoft offers the “Your Phone” Microsoft Store app which just links a Windows 10 PC to a cell phone and doesn’t use the internal mobile broadband adapter. There is a native Windows 10 (not Microsoft Store) utility called “Mobile Broadband SMS Toolkit” available here for free. Note that the developer is Russian and the web site is hosted in Latvia, so if you handle sensitive information on your computer you may want to further evaluate the situation before installing the app.

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In addition to sending and receiving SMS messages, the app has quite a few other functions, including managing contacts and displaying a lot more information than Windows provides. As you can see, the “Current data class” is LTE:

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Performance is quite good (measured with Ookla Speedtest). The DW5808 has a theoretical speed of 100Mbit/sec down and 50Mbit/sec up. I have never seen a download speed faster than around 40Mbit/sec. This could be due to a number of factors, including the computer lid not having the correct antennas for all of the frequencies used by this modem, or simply comes from network congestion (this is New York City, after all). Upload performance is quite good at 44Mbit/sec which approaches the theoretical maximum of 50Mbit/sec:

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Studio 1558 BIOS with all features unlocked – improved thermal settings and more

One of the frequent issues people reported with the Studio 1558 when it was released was overheating. Some configurations were on the edge of reliability, particularly with the thermal pads Dell used, which weren’t ideal for the higher-power CPUs. Dell made some changes in BIOS A04/A05 to improve thermal management somewhat, but those settings are not user-configurable in the stock BIOS. Combined with the direction of airflow and the difficulty in reaching the fan for cleaning, that meant that airflow could be restricted by the surface the computer was used on and large balls of dust could also build up between the fan and the radiator fins.

People came up with all sorts of solutions involving polishing the heatsink, using expensive heat sink paste and even copper shimming. One of the things people reported was that the fan would never run at full speed, even when the system was close to overheating. The only time it ran at full speed was while flashing the BIOS! I have also found that using the computer with the optional 9-cell battery helps, as the 9-cell version elevates the rear of the computer by around 1″, allowing unrestricted airflow into the bottom vent. With the standard battery, there is only 1/8″ or so between the bottom of the notebook and the surface it is sitting on. Of course, regardless of which battery is installed, it is important to not use this computer on a soft surface or anything else that might obstruct airflow.

Way back in 2011 a user named “kizwan” on the Notebook Review forum posted a modified A11 BIOS for the 1558 and subsequently updated it to the A12 BIOS per my request. It enables all of the submenus present in the Phoenix BIOS. Not all of those features apply to the Studio 1558 and as these menus were never enabled in the released BIOS, there are typos. For example, the “CPU Control Sub-menu / LPC Control Sub-menu” is completely empty and “Clarksfield” is mis-spelled “Clsrksfield” in at least one place. Also, some of the explanatory text for some menu items wraps around to the left side of the screen. None of these cosmetic issues in BIOS setup affect regular operation of the computer as they only appear in BIOS setup.

It is possible that changing some of the now-visible additional settings could put the 1558 into a non-bootable state. In that case, just disconnect the AC power adapter and the battery, then open the user access cover on the bottom of the 1558 and remove the CR2035 coin cell. Push the power button on the side of the computer to discharge any remaining “flea power” and clear the CMOS settings, then reinstall the coin cell, replace the user access cover and reconnect the battery and AC adapter. On power-up, the BIOS should report that the CMOS settings are invalid and let you enter BIOS Setup by pressing F2.

There is one known interaction which may or may not present a problem – if you enable “VT-d Technology” in the “CPU Control Sub-Menu”, the computer cannot boot from removable USB media. This is not limited to the Studio 1558 BIOS – a number of other systems from the same timeframe have reported similar problems.

Here is the menu with the various fan temperature thresholds. In this picture I have changed the defaults to turn the fan on earlier and faster:

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I have been running this BIOS for nearly 10 years and have not had an overheating problem, including in Death Valley when it was 126° F and several weeks per year every year since 2015 in the Mojave Desert where the temperature was always over 100° F. I do disassemble the computer annually to clean out the dust from the fan as well as blowing the desert sand out of the keyboard.

In case the MediaFire page vanishes, I have saved a copy of the file here. You can verify that the MD5 checksum matches the one in the original Notebook Review post.

The Dell Studio 1558 – Still a nice laptop in 2021

I’ve had a number of Dell Studio 1558 laptops for well over 10 years now. Occasionally people ask me “Why do you still have that old thing? You need a newer/faster/better system!” Actually, I don’t and I’m going to explain why.

The Studio 1558 (as I have configured or built them) has lots of still-relevant features, like:

  • Quad-core i7-740QM CPU with Hyperthreading
  • Discrete AMD HD5470 graphics
  • 16GB of user-expandable memory instead of being soldered in
  • Backlit keyboard with sculpted keys and 3 backlight intensity levels
  • Full-HD (1920 x 1080) screen w/ matte (anti-glare) finish
  • 1TB Samsung 860 EVO SSD
  • 6x Blu-ray recorder
  • Integrated 802.11a/b/g/n/ac/ax WiFi using Alfa AWPCIE-AX200U (based on Intel AX200) card
  • Integrated Bluetooth 5.1 (included with AWPCIE-AX200U)
  • Integrated 4G LTE universal mobile broadband using Dell DW5808 card
  • Integrated GPS (included with mobile broadband)
  • Built-in SDHC card reader
  • Built-in hardwired Gigabit Ethernet
  • 9-cell battery for extended runtime
  • Readily available schematics, service information and parts
  • Very attractive (IMHO) styling

However, being an 11 year old design, it does have some limitations. In approximate order from most annoying (to me) to least annoying:

  • Limited to 8GB RAM (not really – see my other blog post here)
  • Somewhat lower CPU/memory performance (see below)
  • Lower-end graphics performance for a modern laptop (see below)
  • SATA 2 interface for disk drive and optical drive
  • USB is 2.0, not a newer specification
  • “Gigabit” Ethernet tops out at around 600Mbit/sec
  • The last officially-supported operating system was Windows 7 (but it can run Windows 10 – see my other blog post here)

I don’t use this laptop for gaming, so the graphics performance isn’t a problem. I do some very light Photoshop editing when I’m on the road and posting pictures. The SATA 2 interface isn’t really limiting since I have a Samsung 860 EVO SSD with Samsung Magician software which boosts the speed quite a bit. The only time I miss having USB 3 is when backing up pictures / videos I took while traveling to an external USB hard drive for safekeeping, and that can happen overnight while I’m sleeping.

I’m going to compare the Studio 1558 with the closest-to-equivalent current systems from Dell.

First, let’s consider a Precision 7550 high-end workstation-class system configured as closely as possible to the specs of my Studio 1558 (PDF of Precision configuration here). That currently prices out at $3497.56 list price, $2439.33 sale price. While it has a faster CPU, memory and graphics, it has a keyboard with those annoying flat tops instead of sculpted ones like the ones on the Studio 1558. And it has no provision at all for an internal optical drive.

Next, let’s try a low-end system. Dell’s low-end systems are not customizable beyond selecting a stock hardware configuration with whatever software you want pre-installed. I selected the Inspiron 15 7000 as the model that came closest to the 1558 (PDF of Inspiron configuration here). After selecting 16GB RAM, 1TB SSD and a backlit keyboard, only one configuration remains, with a list price of $1659.99 and a sale price of $1409.99. Again, this has a faster CPU, memory and graphics but also the annoying flat-top keys and no internal optical drive. In addition, it lacks hardwired Ethernet (WiFi only), doesn’t support any mobile broadband options, offers no extended-runtime battery and probably has other drawbacks. It does have a higher-resolution screen than either the Studio 1558 or the Precision 7550 configuration shown above.

I’m picking Dell systems to compare with because they’re the ones I’m most familiar with, service manuals, parts and schematics are readily available, Dell doesn’t make you jump through hoops to prove you’re entitled to download drivers and BIOS updates, and doesn’t do silly things like having the BIOS only recognize officially “blessed” vendor-branded WiFi or other add-in cards. If you know of current non-Dell systems that are close to the Studio 1558’s configuration and reasonably priced, I’d like to hear about them in the comment section.

As far as performance of the Studio 1558, it is quite reasonable. Microsoft still includes the “winsat” benchmarking tool, though it no longer displays the scores on the Control Panel / System page. But if you know where to look:
%windir%\Performance\WinSAT\DataStore\* Formal.Assessment (Initial).WinSAT.xml
you can find the scores. Windows 10 rates the system on a scale of 1.0 through 9.9 instead of the 1.0 through 7.9 scale of Windows 7. Here are the results for one of my Studio 1558 systems running Windows 10:

Overall System Score: 5.1 (lowest of the following scores)
Memory Score: 8.5
CPU Score: 8.5
Graphics Score: 5.1
Disk Score: 7.75

For comparison, the scores on Windows 7 were:

Overall System Score: 5.7 (lowest of the following scores)
Memory Score: 7.7
CPU Score: 7.5
Graphics Score: 5.7
Gaming Score: 6.3 (no longer rated in Windows 10)
Disk Score: 5.9

That shows that a high-end configuration of a Studio 1558 makes a fine Windows 10 machine if you aren’t making extensive use of graphics. Just for comparison, this is the Windows 10 winsat result from a high-end (Precision 3630 with Xeon E-2286G CPU, 32GB 4-way interleaved RAM, Radeon Pro WX7100 graphics and a 1TB Class 60 NVME drive) workstation costing over $5000:

Overall System Score: 8.7 (lowest of the following scores)
Memory Score: 9.3
CPU Score: 9.3
Graphics Score: 8.7
Disk Score: 8.9

I’m happy with that.

Please note that the above benchmarks and my “seat of the pants” performance opinion is based on a system with an i740-QM CPU (this was the top-end CPU offered by Dell in the 1558), 8GB or 16GB of RAM, and a fast 1TB SSD running Windows 10 x64 LTSC. As part of the research for this article, I used a 1558 with an i5-520M CPU, 4GB of RAM and a 320GB mechanical hard drive, running Windows 10 Pro 20H2. Saying the overall experience was quite unpleasant would be a bit of an understatement. Simply restarting Windows had the disk saturated at 100% for well over 10 minutes as shown by the Task Manager / Performance window. A SSD would certainly have helped, but the 4GB RAM certainly caused a lot of paging activity. Given the cost of the upgrades today, it seems silly to not upgrade a Studio 1558 to a top-spec system.

With the computer running Windows 10 LTSC and Office 2019 Professional Plus, I felt it was only fitting to update the palmrest badges to reflect this. This is the original “Energy Star” sticker from 2010, but the CORE i7 badge has been updated to the latest style, the Windows 7 badge was replaced with a Windows 10 one, and an “Office 2019 Professional Plus” sticker was added to complete the display. The “Portable4” and “Backup PC” labels indicate the hostname on my network and that this is one of 3 identical Studio 1558 computers, one labeled “Real PC” that goes on the road with me when I travel, and 2 labeled “Backup PC” in case something happens to the real PC.

Click on the image for full-screen view

16GB RAM on a Studio 1558 is possible!

As part of an upgrade of my Dell Studio 1558 computers to Windows 10 (you can find all of my Studio 1558-related posts here), I decided to investigate the possibility of actually installing 16GB of RAM in each one. This is theoretically impossible according to Dell. So I checked the Intel Ark page for the Core™ i7-740QM CPU and it also says “Max Memory Size (dependent on memory type) 8 GB”. Pretty definitive, right?

Getting into the technical nitty-gritty, “Intel® Core™ i7-900 Mobile Processor Extreme Edition Series, Intel Core i7-800 and i7-700 Mobile Processor Series Datasheet – Volume One” (document number 320765-001, September 2009) is quite clear on pages 20-23 that the largest DIMM configuration supported is two 4GB modules. The “Intel® Core™ i7-900 Mobile Processor Extreme Edition Series, Intel® Core™ i7-800 and i7-700 Mobile Processor Series – Specification Update” (document number 320767-028US, February 2015) doesn’t say anything about support for increased memory sizes.

Not that that has ever stopped me before… I checked the Crucial web site (not that I’m a big fan of Micron/Crucial, but they are a memory chip manufacturer as well as selling memory modules) and they also list 8GB maximum memory, using 2 CT51264BF160B 4GB modules. This is a DDR3L-1600 part with 11-11-11 timing at that speed. That is a faster part than the Studio 1558 needs, since the fastest memory any of the CPUs in the 1558 need is DDR3-1333 with 9-9-9 timing. Fortunately, most things are perfectly happy with faster memory, even if they won’t make use of it. Cisco excepted, of course.

It turns out that Crucial makes that exact same spec of memory in an 8GB module, the CT102464BF160B. At only $37.95 each from Amazon, it seemed like a fun project to order two of these modules and see what would happen. And this was the result:

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So far, so good. But what would the longer-term reliability be like when the system was heavily loaded? I decided to run Memtest86+ 4.20 (available here) to see:

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At that point it had run solidly for 3 passes / 11 hours in Memtest86+. So I think it is safe to assume that this will work for the long term. This image also shows that the full 16GB is cacheable – sometimes when experimenting with oversized memory configurations only part of the memory is cacheable, leading to inexplicable random-seeming performance drops. Not shown in this picture, but displayed on another Memtest86+ screen, is that the memory is operating in fully interleaved mode, which Intel refers to in the datasheet as “Dual-Channel Symmetric Mode” which provides maximum performance. This is the same mode that 2 * 4GB memory operates as. so there is no performance loss with the larger memory.

Of course, Dell and Intel both saying that it is unsupported means that you’re doing this at your own risk. It is not like any of these notebooks or CPUs are still in production (or even under warranty) at this point, 10+ years later. IMPORTANT: I have only tested this with the 4DKNR motherboard (discrete ATI HD 5470 graphics) and an i7-740QM (S-spec SLBQG) processor with BIOS version A12. It may not work with other motherboards, CPUs or BIOS versions.

I have a number of theories as to why this was listed as unsupported:

  • At the time, 8GB memory modules were very rare in the SODIMM form factor. The memory controller (integrated on the CPU die in the i7-740QM processor) only supports 2 memory sockets.
  • Large-memory configurations were not that popular in Dell notebooks (at least in the Studio 1558 class) at the time. I’m told that the vast majority of Studio 1558s sold by Dell shipped with either 4GB (2GB * 2) or 6GB (4GB + 2GB) of installed memory.
  • Dell sold the Studio 1558 with a wide variety of CPUs with either integrated graphics or discrete graphics. It is possible that some of the CPUs or motherboards were actually limited to 8GB and it was just easier to say that they all had an 8GB limit. That doesn’t explain the Intel Ark pages also being incorrect, though.

I did try a pair of 16GB modules (the CT204864BF160B) and they did not work – neither a pair of modules for a total of 32GB nor a single 16GB module in either the DIMM A or DIMM B socket were recognized – all resulted in the 4 beeps indicating “Memory read / write failure”. It is interesting that the error was not the 2 beeps of “No Memory (RAM) detected”, so the system definitely determined that there was memory installed, it just didn’t know how to deal with it. Given that a) We’re talking about trying to fit 32GB in a 10-year-old laptop, b) Most new laptops ship with 16GB or less, and even Dell’s current Alienware gaming laptops have more 16GB models than 32GB models, and c) The cost of a pair of Crucial CT204864BF160B modules, which works out to around US $300 at present, makes it economically impractical to do, since for $300 you can get a very nice whole used Studio 1558 with discrete graphics, 1920 x 1080 screen, etc. I think any further pursuit of this and related stunts like trying a Core i7-940XM is the computing equivalent of “They’ve gone to plaid!” (click the link if you don’t get the Hyperdrive joke from the movie “Spaceballs”).

Reversing airflow on Cisco 3945 routers

The Cisco 3945 router ships with the default airflow “backwards” (back-to-front) compared with all other standard Cisco routers and switches. While back-to-front is available on a number of Cisco producta, as either a factory option (for example, the Catalyst 4948E-F) or as a field conversion (for example, the Catalyst 4500-X-16SFP), the 3945 is the only Cisco device I’ve encountered which defaults to a back-to-front airflow. There is an optional fan assembly (3900-FANASSY-NEBS) which has front-to-back airflow, but it is hard to find and represents a large additonal expense, since your 3945 presumably has a fan tray already that is working perfectly (but backwards).

This article shows how to convert a fan tray from the standard 3900-FANASSY to 3900-FANASSY-NEBS with the only new part required being an inexpensive (pennies) jumper and your time to do the conversion. NOTE: While it is possible to do this (with practice) by removing the fan assembly from a running 3945 and converting / reinstalling it before the 3945 shuts down from overheating, I suggest that you power down the 3945 first to avoid the problem. If you are converting multiple units, you can shuffle converted and un-converted fan assemblies with no downtime.

You will need the following tools and supplies:

  • Small needlenose pliers
  • Small diagonal cutters
  • Phillips screwdriver
  • Several small cable ties
  • Fan mode jumper (more on this below)

The “fan mode jumper” is just a short (1″ or so) length of wire with the correct pins on each end. The pins are Molex part number 39-00-0039, 18 cents each. The tool to crimp them is Molex part number 64016-0200, which is quite expensive at $137.21. However, you can get creative and use the small needlenose pliers to manually crimp the pin onto the cable. If you do this, I suggest also soldering the pin to the cable (after crimping) to ensure a good mechanical and electrical connection.

This is the jumper wire and the small cable ties (each picture is clickable to show a higher-resolution version):

Following the Cisco instructions, remove the bezel and the fan assembly from the router. Place the fan assembly face-down on your work table and remove the 8 Phillips screws holding the two halves of the fan tray together, as indicated by the circled red areas in this picture. Your fan tray may or may not have screws in the circled yellow areas; you do not need to remove those. This is a new spare fan tray – your fan tray will likely be a lot dustier:

Carefully separate the two halves of the fan tray. One piece is only sheet metal – set that one aside for later. The other piece has the fans, wiring, and connector. That is the piece we will be working with. There is also a small clear plastic light pipe, as shown in this picture. Carefully remove it and set it aside for later:

Each fan is held in place with 4 blue silicone rubber stakes. Here is a view of one of the fans:

Starting with the rightmost fan (numbered 4 in the stampings on the tray), using the needlenose pliers, gently squeeze the expanding “V” part of the stake and carefully lift that corner of the fan up. Repeat with the 3 remaining corners of the fan and lift the fan out:

You may need to use the small diagonal cutters to cut a cable tie holding the fan wires in place if you don’t have enough slack to perform the next step. Flip the fan over so what was the top of the fan is now on the bottom (one side will have a part number sticker while the other side will be blank). Re-install the fan on the 4 blue silicone rubber stakes, and while gently pulling on the free “tail” of the stake, push the fan down against the metal of the fan tray until the expanding “V” part pulls through the fan. Repeat for each of the 4 remaining fans.

When you have the next-to-rightmost fan out, you will see the back of the connector that connects the fan tray to the router:

The red arrows in the previous picture show where the jumper needs to be installed. Bend the jumper into a “U” shape and carefully insert it into the connector until it clicks. You should end up with it looking like this:

Once you have all 5 fans flipped over, examine the underside of the fan tray to make sure there are no wires sticking out and that the fans are all fully seated on the blue silicone rubber stakes. An un-seated stake will generally appear slightly “popped out” when you look at the underside of the fan tray.

Use the small cables ties to replace any ties you had to cut to get enough slack to flip the fans over. Next, re-install the light pipe. The small U-shaped bend lines up with a matching protrusion on the sheet metal, shown with an arrow in this picture:

Carefully re-install the other sheet metal half of the fan tray that you set aside at the beginning. You may have to wiggle the light pipe a bit to get it to line up with the holes in the fan tray. Make sure that the two halves of the fan tray are fully seated on each other with no protruding pieces (there are interlocking metal tabs on the two halves). Also make sure that no wires are sticking out or being pinched. If all looks good, re-install the 8 Phillips screws. Give the fan tray another look-over to make sure everything is in place, then re-install it in the router and power up the router. Once the router has booted, use the “show environment all” command to verify that all 5 fans are operating correctly and that the router has detected the new jumper and is operating in front-to-back mode:

 Fan Tray: Installed with Reverse Air Flow. Air Filter Supported.
 Fan 1 OK, Low speed setting
 Fan 2 OK, Low speed setting
 Fan 3 OK, Low speed setting
 Fan 4 OK, Low speed setting
 Fan 5 OK, Low speed setting

Technical minutiae: The only thing the jumper does is tell the router that a front-to-back airflow fan tray is installed. If you don’t install that jumper, the router will still operate with front-to-back airflow but the environmental readings will indicate that the unit is an “air conditioner” (exhaust air is cooler than intake air):

 Fan 1 OK, Low speed setting
 Fan 2 OK, Low speed setting
 Fan 3 OK, Low speed setting
 Fan 4 OK, Low speed setting
 Fan 5 OK, Low speed setting

 Intake Left temperature: 18 Celsius, Normal
 Intake Right temperature: 17 Celsius, Normal
 Exhaust Right temperature: 16 Celsius, Normal
 Exhaust Left temperature: 17 Celsius, Normal
 CPU temperature: 49 Celsius, Normal
 Power Supply Unit 1 temperature: 21 Celsius, Normal
 Power Supply Unit 2 temperature: 22 Celsius, Normal

As you can see, exhaust air is being reported as 1 degree cooler than entering air. This is because the router doesn’t know the airflow is reversed, so the sensors behind the fan tray are being treated as exhaust and the sensors by the rear I/O panel are being treated as intake. Installing the jumper lets the router know airflow is reversed and that it should report the rear I/O panel sensors as exhaust and the sensors behind the fan tray as intake:

 Fan Tray: Installed with Reverse Air Flow. Air Filter Supported.
 Fan 1 OK, Low speed setting
 Fan 2 OK, Low speed setting
 Fan 3 OK, Low speed setting
 Fan 4 OK, Low speed setting
 Fan 5 OK, Low speed setting

 Left Intake temperature: 20 Celsius,  Normal
 Right Intake temperature: 18 Celsius,  Normal
 Right Exhaust temperature: 20 Celsius,  Normal
 Left Exhaust temperature: 21 Celsius,  Normal
 CPU temperature: 61 Celsius, Normal
 Power Supply Unit 1 temperature: 23 Celsius, Normal
 Power Supply Unit 2 temperature: 25 Celsius, Normal

Note: the two “show environment all” reports above were performed at different times, thus the differing temperature readings. There is no difference in cooling efficiency when reversing the airflow direction.

FreeBSD – Restoring inappropriately removed lang/php56 port

FreeBSD removed the lang/php56 port from the ports repository (in commits r488887) through r488894, approximately). This is due to a misunderstood “2019-01-01 lang/php56: Security Support ends on 31 Dec 2018”.

However, says (emphasis added by me):

PHP 5.6.40 Released – 10 Jan 2019

The PHP development team announces the immediate availability of PHP 5.6.40. This is a security release. Several security bugs have been fixed in this release. All PHP 5.6 users are encouraged to upgrade to this version.

For source downloads of PHP 5.6.40 please visit our downloads page, Windows source and binaries can be found on The list of changes is recorded in the ChangeLog.

Please note that according to the PHP version support timelines, PHP 5.6.40 is the last scheduled release of PHP 5.6 branch. There may be additional release if we discover important security issues that warrant it, otherwise this release will be the final one in the PHP 5.6 branch. If your PHP installation is based on PHP 5.6, it may be a good time to start making the plans for the upgrade to PHP 7.1, PHP 7.2 or PHP 7.3.

FreeBSD removed the php56 port and dependencies as of 5.6.39. Users may be depending on either PHP 5.6 semantics, or on a port that was removed (such as devel/pecl-intl) as “collateral damage”.

I needed to restore these kits for those reasons. While I will be migrating to a PHP 7.x release with the next major rebuild of the systems in the coming month, I needed to deploy the 5.6 security fixes before then. I created a kit that restored many (but not all) of the removed ports, which you can download here. Security conscious users should NOT blindly install kits from untrusted sources like me, but instead create their own kits by looking at the official FreeBSD ports tree here. However, if you just need a quick fix and trust me, feel free to use my kit:

cd /usr/ports
tar -xpvf ~/php56-restore.tgz
mv MOVED /usr/ports/
mv /usr/ports/Mk/Uses/
portupgrade -an (to see what ports will be updated)
portupgrade -ai (interactively approve/deny updating individual ports)

Note that my kit does modify 2 “global” ports files – MOVED and You may wish to restore the official versions after updating your php56 ports to avoid possible issues with other ports (though restoring MOVED will also restore the warnings about php56 ports being EoL and removed, and will try to update your php56-extensions if you let it).

Proctor-Silex / Hamilton Beach Vegetable Steamer / Rice Cooker Model C36507 / 36500

We have a Proctor-Silex C36507 Vegetable Steamer / Rice Cooker which we’ve had for ages. Somewhere in our various moves, the manual got separated from the gizmo (personally, I suspect Sue’s piano ate it). For the stuff we usually make, that’s no big deal – dump in water, dump in vegetables, set timer. Tonight we decided to make rice instead of going out in the 100-degree heat to the local Chinese restaurant like we usually do. Of course, the 25-word summary on the back of the unit doesn’t go into details about cooking rice, and the rice bag was similarly un-helpful.

Dinner was delayed a bit while we both scoured the Internet looking for a copy of the manual – after all, the Internet has everything – so why wouldn’t it be available there? Well, you’d probably be surprised – we were. There were a lot of requests from people looking for the same manual, without any luck. I did find a manual on However, it was a not-so-great scan of a nearly 25-year-old FAX of a printer’s draft of the manual, complete with crop marks and various spots of indeterminate origin. That wouldn’t be so bad, except that aside from the front and back covers, the actual manual pages had been shrunk to only occupy around 1/4 of each 8.5″ x 11″ page. Since there’s no room in our small kitchen for a microscope to read that, I did a bit of work in Photoshop to resize, crop, and clean it up. The resulting printout is currently occupying a place of honor in the kitchen (on the side of the fridge).

On the off chance that you’re one of the dozens of people looking for this manual, I’ve put a copy on my web site here (PDF) to save you the trouble. Note that this is the same manual you can get from ManualsLib, just cleaned up. All credit for tracking down this elusive beast goes to them.

Net Neutrality isn’t the only problem

Today (July 12th, 2017) a large number of sites have joined together to raise awareness of the threats to network neutrality. For example, reddit has a pop-over window that slowly types a message beginning with “The internet’s less fun when your favorite sites load slowly, isn’t it?” This is certainly a valid concern, and many people, including myself, have legitimate concerns about how the Internet is regulated. But there are enough sites raising that point, so I’d like to talk about something different – how sites are “shooting themselves in the foot” with slow-loading (and often buggy) page content.

It all starts when a web site decides they want to track visitors for demographics or other purposes. There are a large number of “free”* tools available that will collect the data and let you analyze it in any way you like. Sure, it comes with some hidden Javascript that does things you can’t see, but hey – it is only one thing on a page of otherwise-useful content, right?

Next, the site decides they’d like to help cover the cost of running the site by having a few advertisements. So they add code provided by the advertising platform(s) they’ve selected. So their page now loads a bit slower, and users see ads, but the users will still come for the content, right? And the occasional malware that slips through the advertising platform and gets shown on their site isn’t really their fault, right? They can always blame the advertising platform.

Somewhat later, the site gets an “offer they can’t refuse” to run some “sponsored content”. The page gets even slower and users are having a hard time distinguishing actual content from ads. Clicking on what looks like actual content causes an ad to start playing, or triggers a pop-under, or any one of a number of things that make for an unpleasant user experience.

Once everyone is used to this, things appear to settle down. Complaints from users are infrequent (probably because they can no longer figure out how to contact the site to report problems). Everyone has forgotten how fast the site used to load, except for the users running ad blockers, cookie blockers, script blockers, and so on.

But one day a SSL certificate becomes invalid for some reason (expired, a site was renamed, etc.) and the users are now getting a new annoyance like a pop-up saying that the certificate for is invalid. Most users go “huh?” because they weren’t visiting (or at least they thought they weren’t visiting) Clicking the “close” button lasts for all of a second before the pop-up is back, because that ad site is determined to show you that ad. In frustration, the user closes their browser and goes out to buy a newspaper.

By this point, perhaps 5% of the actual page content is from the site the user was intending to visit. The rest is user tracking, advertising, and perhaps a bit of malware. There is a free tool run by which will let you analyze any web site to see what it is loading and why it is slow.

Here is the result for the CNN home page:

Now, that’s too small to be able to read, so this is the first part of it (click on this image for a larger view):

The blue line at 21 seconds shows when the page finished loading, although you can see that Javascript from a number of advertising providers continues to run indefinitely.

Now, let’s take a look at Weather Underground. Surely just serving weather information would have far less bloat than CNN, right? Not really:

Now, that’s too small to be able to read, so this is the first part of it (click on this image for a larger view):

It does manage to load in less time than CNN, but it is still pretty awful.

In the spirit of full disclosure, here is the result for this blog page:

Since the entire report fits, I didn’t need to add an unreadably-small overview image.

If you manage a web site, I encourage you to try yourself and see why your site is slow. If you’re just a user, you can also use to see why the sites you visit are slow. If you’re using add blocking or site blacklisting software while you browse, the list of hosts that are serving advertisements or other unwanted content will probably be useful to you when added to your block / blacklist.

* As they say, “If you aren’t paying for it, then you are the product being sold”.

Soviet PDP-11 Clones

In addition to having a domestic computer design industry (see Pioneers of Soviet Computing [local copy]), the Soviet Union was well-known for copying computer designs from the West. While there were many possible reasons for this, one of the most commonly given ones was the desire to run specific software, also from the West. This could be a particular application program or a whole operating system. Certainly, not having to write software in order to have a deliverable computing product was a huge benefit to the Soviets. While the scale of this cloning program was not entirely understood by the West during the Soviet era (see Total Soviet Computing Power [local copy]) it was well known that a good deal of cloning was going on.

Steal the best
Image courtesy of FSU’s Silicon Zoo

DEC supposedly inscribed the phrase “VAX – When you care enough to steal the very best” on an otherwise-unused area of the die for one of their MicroVAX CPUs. The phrase in the picture reads “СВАКС… Когда вы забатите довольно воровать настоящий лучший” which is horribly mangled Russian, but I think it got the point across.

The highest-performing PDP-11 CPU DEC built was based on the DCJ11 (or J-11, or Jaws), microprocessor. This CPU was the basis for all subsequent DEC PDP-11 products (PDP-11/53, /73, /83, /84, /93 and /94) up until they sold the product line to Mentec, who continued to use the J-11 on their M70 / M71 / M80 / M90 and M100 CPUs. It was not until nearly 4 years had elapsed after Mentec acquired the DEC PDP-11 line that they introduced a new design, the M11, not based on the J-11. This was probably due to the last J-11 chips being manufactured in early 1998, as production was apparently stopped as soon as Compaq acquired DEC.

The J-11 design was not without its problems. It was a joint manufacturing effort of DEC and Harris Semiconductor (Intersil). DEC had previously used the Harris / Intersil 61×0 chips, which implemented the PDP-8 CPU in a microprocessor. They probably weren’t expecting the issues which plagued the J-11 project. In addition to problems with the CPU itself, there were problems with the optional floating-point accelerator chip (designed and built entirely by DEC) and the support chips needed to make the J-11 function in a system. This led to a number of costly recalls by DEC to fix (or conceal) problems. The original distinction between the various PDP-11 systems based on the J-11 was lost as parts (normally the floating-point accelerator chip) were removed and / or the board swapped for a slower 15MHz one in the field to get the systems working reliably. Eventually the J-11 systems became reliable enough that users could have an 18MHz CPU with working floating point. Earlier J-11 chips had speed restrictions (often 15MHz) and did not work with the floating-point chip. The planned optional Commercial Instruction Set (CIS) option was never produced, although you can see where it would have been placed on the bottom side of the CPU.

Certainly not all of the problems were on the Harris side – I’ve successfully run a J-11 at 24MHz on a 3rd-party board. The DEC support chip set was found to be limited to a bit over 18 MHz, which is why DEC did not press Harris particularly hard to meet the 20MHz design goal (for top-binned parts). The part number DCJ11-AE (the -AE suffix indicated the revision level) was the last version produced, the “good one”. Interestingly, the individual chips on the first DCJ11-AE CPUs were revision 1 on the DC334 chip and revision 11 on the DC335. The newest DCJ11-AE I’ve seen (with a module date code of 9820 and chip date codes of 9819) has a revision 4 DC334 chip and a revision 16 DC335 chip. That DCJ11-AE has the Harris logo stamped on the ceramic carrier as well as the individual chips, while a somewhat earlier sample with a 9711 date code has the same revision 4 and 16 chips, but without Harris markings on the ceramic carrier. 9820 is pretty close to the time DEC was acquired by Compaq, so the J-11 hung on to the bitter end, 4 years after DEC sold the rest of the PDP-11 business to Mentec. Apparently there weren’t user-visible changes which would cause the overall CPU revision to change to a DCJ11-AF. Perhaps the changes were to simplify the manufacturing process.

DEC also “shot themselves in the foot” by having one group think the part was solely for DEC’s use in building systems, while another group was trying to get design wins in 3rd-party products. This led to a bizarre situation where if you tried to purchase a J-11 chip by itself from DEC, you got a call from the J-11 product manager (Cathy Berida) who was forced by upper management to ask you what you planned on doing with it before the order would go through. Needless to say, DEC did not get a lot of OEM design wins due to their inconsistent policies regarding the chip. The result of this is that you can purchase case lots of never-used J-11 chips on places like eBay [local copy] if you happen to need a few hundred of them.

DEC M8192

Image courtesy of ElectronTubeStore

[This and all subsequent images in this post are clickable to show a higher-resolution version.]

This is a DEC M8192 module, used in the PDP-11/73 systems. It has an older J-11 CPU and no floating-point accelerator (FPA) chip (the large empty socket below the white J-11 CPU). A manual for it is available from Bitsavers [local copy]. Note that the manual doesn’t show the socket for the FPA, and the sole mention of the FPA is in the description of the internal J-11 CPU registers.

Soviet M8

Image courtesy of eBay user ru.seller

This is a Soviet M8 CPU board. It looks suspiciously like the DEC M8192 board, doesn’t it? Aside from some component substitutions due to limited availability of things (like PLCC sockets for the support chips and the compact 4-LED display) it is pretty much the same board. Note that this board doesn’t even have a socket for the floating-point accelerator chip. The pads are on the board, but there is no socket. This may indicate that the clone parts were created before DEC got the various design issues ironed out. Additionally, the configuration jumpers are soldered in instead of being removable jumpers as they are on the DEC board. The board in the picture is non-functional as some components (mainly bypass capacitors) have been removed for some reason.

Soviet M8 detail

Image courtesy of eBay user ru.seller

Examining the M8 board in more detail, we can see some very interesting things. At the top center of theis image, you can see two chips with the logo “MHS” and the date code “USA8616”. If you’ve never heard of MHS, I’m not surprised. They were a relatively obscure manufacturer of specialty ICs. MHS stands for “Matra Harris Semiconductor” – yup, the same Harris Semiconductor that was making J-11 parts for DEC. They probably had no idea their parts were ending up in the Soviet Union – often, “front” companies would purchase parts in the West and those parts would eventually make their way into the Soviet Union.

The MHS part is a HM3-65747-5 CMOS 4K x 1 static RAM. The DEC M8192 board, oddly enough, does not use the MHS part. Instead, it uses a National Semiconductor NMC2147HN-3 which appears to be a pin-compatible substitute.

Also in this detail image, you can see 5 parts where the manufacturer and part number information has been ground off and “РУ12” written on on them with a marker pen. There is another of these parts outside the area of this detail. On the DEC M8192, these are Fairchild MB8168-55 NMOS 4K x 4 static RAM. “РУ” was the Soviet type designator for a memory chip. One of the chips on the Soviet board does not have its identifying marks removed, and it appears to be an INMOS IMS1420D-55, also an NMOS 4K x 4 static RAM. The mysterious РУ12 is probably К132РУ12 as this page and this page both show that as an interchange part for the IMS1420-55. They’re almost certainly not Soviet-made parts as there would be no need to grind off the original markings in that case.

DEC DCJ11 top

This is the top of a genuine DEC DCJ11-AE. As you can see, there are two large chips mounted to a ceramic carrier. Under the top layer of ceramic you can see some of the leads that connect the two chips to each other and to the pins on the edge of the CPU. There are 4 bypass capacitors for each chip to filter out noise. There is also one SOT-package part (possibly a transistor or 3-terminal regulator) installed, with an unpopulated space for an second one. It possible that the unpopulated space was for a part intended to be used on the underside of the CPU.

DEC DCJ11 bottom

The bottom view of the same part shows the pads which would have held the Commercial Instruction Set if it was ever implemented. You can also see additional leads in an intermediate ceramic layer – the ceramic carrier was a complex, multi-layer affair.

DEC DCJ11 angle

This angle view shows how the individual chips were soldered to the ceramic carrier.

DEC DCJ11 edge

Looking at the edge of the CPU, you can get an idea how thick the ceramic actually is on this part.

Soviet 1831 top

Here is where things get interesting. This is a Soviet 1831 clone of the J-11. The logo on the chips indicates that it was made by the NPO Electronics (НПО Электроника) factory (now VZZP) in Voronezh. Instead of the DC334 and DC335 numbering on the DEC chips, the chips on this board are labeled КН1831ВМ1 and КН1831ВУ1. Wikipedia has a detailed article on Soviet integrated circuit numbering, but it breaks down as follows:

  • К – Commercial / consumer component
  • Н – Ceramic leadless chip carrier (the individual chips on the CPU carrier)
  • 1 – Monolithic integrated circuit
  • 8 – Microprocessor
  • 31 – Number in series
  • ВМ – Microprocessor
  • ВУ – Microcode
  • 1 – Variant

Apparently the two chips had their own code names – Тунгус 1 (Tungus 1) for the КН1831ВУ1 and Теорема 2 (Theorem 2) for the КН1831ВМ1.

You can see the somewhat different method of attaching the pins to the carrier, compared to the DEC CPU. This is due to the thinner carrier as I will discuss below. The same four bypass capacitors are present, but the SOT-package part found on the J-11 is not, although the pads are there. The chips appear to have been hand-soldered onto the carrier. While the carrier in this picture is blue, variants with white and greenish carriers have been photographed. While this part is just labeled M-2-1, other newer samples have been labeled М8К ред4 (M8K red4).

Soviet 1831 bottom

The bottom of the 1831 shows a much simpler method of construction, compared with the DEC J-11. No additional leads are visible and the only marking is “0133”. It is not known what this means – as the chips on the carrier have 8905 and 8904 date codes, it doesn’t make sense that the CPU would have remained unassembled for twelve years. Perhaps it was the date it was installed into or removed from a system?

Soviet 1831 angle

This angle view clearly shows the hand-soldering of the chips to the carrier.

Soviet 1831 edge

The edge view shows how much thinner the carrier is compared to the DEC J-11.

Soviet 1831 chip top

This detail shows the top of an unmounted КН1831ВУ1 chip. It is interesting that while the fabrication method was quite different from the DEC version, they apparently went through a lot of effort to match the packaging exactly. Perhaps they were trying to substitute the КН1831ВУ1 and КН1831ВМ1 chips one at a time onto a DEC package during development? That would not explain why this unusual packaging continued into production, though.

Soviet 1831 chip bottom

The bottom of the unmounted КН1831ВУ1 is pretty boring, having only a stamped “35”. This does not match the date code on the top of the chip, 9111, so perhaps it is an inspection mark.

Soviet 1811 top

This is an 1811 (DEC F-11, PDP-11/23 and /24) clone CPU. Unlike the 1831, this assembly is not a drop-in equivalent to any DEC F-11. It contains КН1811ВМ1, КН1811ВУ1, КН1811ВУ2 and КН1811ВУ3 chips. That would be a processor and 3 microcode ROMs. This is equivalent to a DEC F-11 and a DEC KEF11-AA FPU (Floating Point Unit). Oddly, in the DEC implementation the KTF11-AA MMU (Memory Management Unit) is necessary for using the KEF11-AA as the FPU reuses some of the registers in the MMU. This chip is marked МК1 ред1 (MK1 red1). The logos on the chips show that they were fabricated by NPO Electronics, same as the J-11 clone.

Soviet 1811 bottom

The bottom shows that the CPU is made with a brown ceramic instead of the white ceramic (with blue top coating) used on the 1831. The bottom is marked 8821, which corresponds roughly to the date codes on the individual chips (8808 through 8811). Too faint to be seen clearly is the writing “26-027” across the top of the chip as shown in this picture).

Soviet 1811 angle

An angle view, clearly showing the “MK1 red1” marking.

Soviet 1811 edge

Here you can see that the carrier is also quite thin, similar to the 1831.

Elektronika 89 board

Image courtesy of Soviet Digital Electronics Museum – Sergei Frolov

This is the CPU board from the Elektronika 89 minicomputer. You can see the 1811 CPU, along with the КР1811ВТ1 MMU chip, in the center of the board.

I hope you’ve enjoyed this look at a relatively unexplored (in the West) area of computer history. These parts occasionally show up on eBay where they often sell for inflated prices. Not all of the eBay listings have the parts described correctly, so rely on pictures (as long as they’re not “sample image only”) to see what you’re getting.