thenetworkinglab.bsky.social
@thenetworkinglab.bsky.social
I'm astounded by the abilities of the members of this community and am thankful 🙏 for everyone's passion and work to keep these old systems going. #retrocomputing - oh, and there's no sponsorship here; I paid for all these parts/things myself and the links are just hopefully helpful shout-outs 🙂 8/8
December 13, 2025 at 11:19 PM
So how does it work/look? One word: spectacular. I've re-posted the RF below (left), along with the TIARA's composite output (middle - great!) and S-Video output (right - superb!). The color detail on the brick wall, and the pixel clarity on the log really show off the abilities of this mod. 7/8
December 13, 2025 at 11:19 PM
A composite mod had been on my 'to-do' list for a long time, but also S-Video? Sign me up. Installation was a breeze - it's all detailed in his video, and I went with the 5-pin DIN option for a clean look, knowing the cables are easy to get and my #retrotink 5X supports 2-RCA luma/chroma input. 6/8
December 13, 2025 at 11:19 PM
But then, a light appeared on the horizon! @theretrochannel.bsky.social posted a YouTube video (www.youtube.com/watch?v=KIfj...) about his new 'TIARA' board (lectronz.com/products/tia...) 5/8
TIARA Atari 2600 S-Video and composite mod
A video upgrade for the Atari 2600/VCS that provides S-Video and composite output
lectronz.com
December 13, 2025 at 11:19 PM
The Atari's famously limited RF-only output - a product of its time - was a bit of a downer. So while a few fun nights were had, it was a bit hard to play - especially on a modern 4K TV (NB the screen shots here are from a smaller, 720p set at my workbench). 4/8
December 13, 2025 at 11:19 PM
It turned out to have a bad AC adapter (a common issue), but it did work and with after making some cartridges for it (thanks to #pcbway and '(DIY) C64iSTANBUL' - www.pcbway.com/project/shar...), it was working great, but... 3/8
December 13, 2025 at 11:19 PM
She kindly gave it to me, saying that she and her sister played it and loved it as kids, but that she tried setting it up for her own kids recently, and it didn't seem to work. While it didn't have any cartridges, it was a pretty complete set. 2/8
December 13, 2025 at 11:19 PM
Some other SCSI cards worth keeping your eyes peeled for are the Adapter AHA-1640 (and variants - the Storage Dimensions version is below) and the Future Domain MCS-350. Sadly, I couldn't get either of these to work - sounds like a good rainy day project! Thanks to ardent-tool.com as always. 12/12
December 6, 2025 at 8:43 PM
Subjectively, the McIDE definitely feels faster than the SCSI adapters as well, but the difference is relatively small. I suspect the McIDE has some internal bandwidth limitation of 2.5MB/s that we're seeing the faster machine hit here, given the same throughput results for all 3 tests. 11/12
December 6, 2025 at 8:43 PM
Here are the benchmarks in a table. The McIDE cards were faster than either the Spock or Tribble cards with a ZuluSCSI, both on access times and throughput. Worth noting that the newer versions of the Spock (I have the oldest) have better throughput (from ardent-tool.com/IBM_SCSI/SCS...). 10/12
December 6, 2025 at 8:43 PM
On to the benchmarks! DiskMeter v1.3 seemed to work reliably, whereas CoreTest 2.7 wouldn't work in some cases. Benchmarks are summarized on the next item in the thread 9/12
December 6, 2025 at 8:43 PM
Another issue is that the IBM SCSI adapters don't seem to work in many PS/2 models; I ran into the same issues documented with a Model 50z here (forum.vcfed.org/index.php?th...) trying to use these in my Model 55SX (they both worked fine in my Model 70) but the McIDE cards worked fine in both. 8/12
IBM SCSI w/cache in PS/2 Model 50 troubles
I am trying to use a Spock Prime/Anosprime SCSI adapter in Model 50z It’s Reference disk finds it ok, and it even seems to work, I see ZuluSCSI’s devices properly, I’d 6 is an attempt to use reference...
forum.vcfed.org
December 6, 2025 at 8:43 PM
Why one vs the other? Well, there are differences in speed as well as availability, cost, and compatibility. The SCSI cards you'll have to find used, and you'll need a ZuluSCSI or similar device, while you can just buy the McIDE models from zzxio.com and a CF card you can get from anywhere. 7/12
December 6, 2025 at 8:43 PM
The McIDE is produced by zzxio.com, and comes in the two variants below, the McIDE, with 2 IDE channels and 2x 40-pin IDE connectors as well as a Molex power connector, while the McIDE-CF is the same but with internal and external CF-card sockets. 6/12
December 6, 2025 at 8:43 PM
Basically 2 options: SCSI MCA cards with a modern SCSI emulator, and an MCA IDE card called the McIDE. Several vendors made MCA SCSI cards, but IBM's two most common for this generation seem to be Tribble (the "SCSI Adapter/A" P/N 15F6561), and the Spock ("SCSI Adapter with Cache" P/N 84F8014) 5/12
December 6, 2025 at 8:43 PM
The problem with these drives is that (aside from the fact they need to be recapped to even work), is that they are starting to die; the one from the picture above works-ish, but is throwing a lot of errors. So what options do we have for these machines? 4/12
December 6, 2025 at 8:43 PM
But 'DBA'? IBM made ESDI drives with an MCA adapter built-in, so these drives are like an MCA version of IDE; they basically plug directly into the MCA bus. The Model 55SX/70 have a 'Slot 4' - which isn't a physical MCA slot, but is actually their disk connector, with only 16 address lines. 3/12
December 6, 2025 at 8:43 PM
What's ESDI? Well, from Wikipedia, it's the Enhanced Small Disk Interface, designed by Maxtor in 1983 to improve on the old Shugart ST-412/506 interface. It had higher transfer rates than the Shugart interfaces but still used their 2-cable scheme, and was popular before IDE and SCSI took over. 2/12
December 6, 2025 at 8:43 PM
Some thanks are owed here. It wouldn't have been possible, or nearly as much fun for me to restore and play with these computers, without the following folks (8/8):
ardent-tool.com
www.youtube.com/@Epictronics1
www.philscomputerlab.com
Ardent Tool of Capitalism
Your go-to destination for everything IBM PS/2 and Micro Channel
ardent-tool.com
November 23, 2025 at 10:52 PM
So - onto the benchmarks. The TL/DR version is that the 25MHz/64KB cache machine is ~120% faster than the SX-16, and 40% faster than the 20MHz/0KB cache machine at Doom.

I have some more disk benchmarking to do - disks in the PS/2 systems are...interesting. But that's a post for another day. 7/8
November 23, 2025 at 10:52 PM
Now this was more like it! The extra clock boost from 20 to 25MHz and the cache provided the snappiness in Windows that I thought I remembered, and games - if not fast, at least weren't slow. Using Pentiums in the 1990s taught me the importance of cache, and this memory turned out to be real. 6/8
November 23, 2025 at 10:52 PM
But still too slow! Windows 3.11 felt sluggish, not snappy. Links 386 took too long to render scenes. A little more research showed me that the 8570-A21 was what I craved - an Editor's Choice machine from 1988 with a 25MHz CPU and 64KB of cache. Luckily, I found one and... 5/8
November 23, 2025 at 10:52 PM
Was this just my memory? Or were these machines really that slow? It was fine for DOS mode, and while the early VGA chipset is slow, but in Windows 3.11 and most games this was...not fast. The problem was - now I had to get something faster! So, onto cleaning up a DX 20MHz Model 70 (8570-121). 4/8
November 23, 2025 at 10:52 PM