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Monday, 2024-08-05

MIPS.COM benchmark program

MIPS.COM is a popular MS-DOS and IBM PC benchmark program from 1980s.

The version of my binary is v1.10, 13312 bytes and the file time stamp is 1987-03-28 (md5sum 2ca6ecb0dbacfb78da35b13ae73aaf8d). No source code is known to be available. However, like with many programs from this era, the disassembly is almost human readable code.

The program has couple annoying cosmetic problems when it's run on a modern PC today, and I have attempted to fix them.

(Click the heading to read more...)

MS-DOS 3.20 FORMAT.EXE bug

I noticed that when using modern emulators and/or BIOS versions, MS-DOS 3.20 fails to format a hard drive (tested using a 32 MB disk):

A>format c:

WARNING, ALL DATA ON NON-REMOVABLE DISK
DRIVE C: WILL BE LOST!
Proceed with Format (Y/N)?y

Format complete

Error reading partition table
Format failure

The above example was produced using SeaBIOS (1.13.0-1ubuntu1.1) and QEMU (4.2.1 (Debian 1:4.2-3ubuntu6.29)). Depending on BIOS, the returned error may also be ``Bad Partition Table''.

This is interesting given that back-in the day MS-DOS 3.20 was used in millions of computers apparently without such an issue.

After some debugging, it seems the root cause is that FORMAT.EXE is trying read the partition table by passing the (0,0,0) CHS address to INT 13h BIOS read disk routine. The routine assumes that sectors start from 1, so depending on BIOS it either rejects the read or reads data from an incorrect location. Apparently this was somehow working when ``real'' CHS addressing was used. Modern systems that convert it to LBA fail.

Tuesday, 2024-07-09

Portable Raspberry Pi Desktop Computer

I wanted to have a small ``portable'' computer that is suitable for word processing and lightweight web browsing (e.g. online banking). I don't like laptops which are non-modular and increasingly non-repairable, so I built a prototype using Raspberry Pi and some spare and recycled items I had around. The inspiration was taken from Commodore 64 executive model that was the first luggable color computer with a small 5" monitor.

(Click the heading to read more...)

Sunday, 2024-06-23

Stable Diffusion on a budget home PC

Thanks to all the hype in the news and at workplace etc. I got interested in AI and tried out Stable Diffusion. It seemed interesting enough to install it locally (I prefer to be self-hosting in about everything), but the problem was I mostly run old legacy recycled hardware, so modern software is not always running that smoothly...

To run it I installed InvokeAI using their instructions which were pretty straightforward. They support a CPU-only mode so basically you can run it on any old hardware. This is good because you can try it out first to see if it's anything you would like to ever use, before splashing money on a GPU.

I was impressed, and a after a few days of experimenting I was confident enough to invest in some new hardware.

(Click the heading to read more...)

Raspberry Pi Power Usage

Given that we have seen the price of electricity sometimes jumping up to near 1 e per kWh here Finland, I have started to pay more attention to the power usage of my computers.

I have many headless Raspberry Pi units running all the time, so I first decided to investigate if there are any simple tricks on them to save power.

Many of the instructions I found were either obsolete (syntax changed etc.) or did not work. I have documented those settings and changes that I was able to measure or observe to have any effect. In the end, this was pretty futile effort. Pi does not consume much to start with, and any savings are even more marginal. But it's fun to tinker.

(Click the heading to read more...)

Thursday, 2024-04-25

The Anarchist's Guide To The BBS

A book by KEITH WADE published in 1990 (Loompanics Unlimited, paperback, 90 pages).

What could be more interesting than reading about computer BBSing? This guide was published on the heyday, and reading it today is a pretty good nostalgia trip. By 1990 I had been personally BBSing already for some years, and running my own systems, networked in the FidoNet. For me it was an escape route from school bullying and boring heavy metal kids, and defined my future ``career'' working in the field of computer programming, telecommunications and open source.

The guide starts by explaining that it is not a technical manual. Perhaps because of this, it's not dated that badly. Still a technology section follows, explaining some of the terms, which are mostly unknown or irrelevant today. Also all the explanations how to use BBSes further in the book are of course still pretty technical and dated. BBSes were command-line oriented. The guide even goes to into some details of RBBS-PC and PCBoard, like ``turbo keys''. Nice trivia. I got flashbacks with all the menus and messages scrolling in my mind.

Anyway, the best part of the book covers how to utilize BBSes from the so-called anarchist point of view, and how they are a great tool for ``subversive speech'', ``dangerous business'', to find cohorts or even participate in crimal activity. Or to just find some friends if you are a misfit. There's also a good point how cheaper technology gives more power to the people. The author talks about ``The Five Hundred Dollar Anarchy Machine''.

Surprisingly, when the BBS-era peaked (and soon collapsed) this was all forgotten. It quickly became money and business driven. Not to enable people, but corporations. This book was apparently even specifically ridiculed (according to EFFector Online, Issue 3.3, 1992-08-24) as ``stupid niche'' at the first ONE BBSCON where ``mainstream businesses'' were promoted. Downfall of USENET and mailing lists soon followed. There was some promise in the early web's ``home page'' era when people were able to express themselves and create content easily. Facebook, twitter etc. killed all this and everything was productized.

I see some potential in Fediverse. And today some kids want to be self-hosting, like we were in the BBS days. This book reminded me why such is important and exciting.

Saturday, 2024-02-03

I'm The Slime

A song by FRANK ZAPPA released on Over-Nite Sensation.

While part of ZAPPA's one of the most easiest and accessible albums, he's never without social commentary. The spoken word lyrics are almost like an lecture, powerful and still relevant as ever. One of the earliest rock critique about TV predating PINK FLOYD's ``15 channels of shit'' by 6 years and BRUCE SPRINGSTEEN's ``57 Channels'' by 19 years.

Backing vocals are by TINA TURNER and THE IKETTES. The legend tells that when IKE TURNER heard some of the material during the sessions, his comment was ``What is this shit?'' and wanted the band not to be credited on the album.

Werewolves Of London

A song by WARREN ZEVON.

A typical song for Zevon as at first impression it's just pretty simple however catchy tune. Then you start to find more levels and connections.

Inspired by an 1935 movie it also refers to modern London. Most notably the restaurant Lee Ho Fook's (apparently now gone). The last time I visited the city I actually went there to eat, around 2005. It was a typical tourist place, a bit pricey, but for a foreigner still something different than home. They also knew about the Zevon song, they featured it in their showcase window along the menu. They had a small picture of him and one of the album covers. I appreciated that.

GRATEFUL DEAD have covered the song in their Halloween concerts.

Monday, 2023-12-25

Bitwoods RBBS-PC

A vintage BBS system running RBBS-PC on MS-DOS. Reachable via telnet or ssh at bitwoods.duckdns.org.

The system is powered by Intel 8086 emulator called tinyxt which is a custom fork of 8086tiny. Compared to e.g. QEMU the emulator provides an order of magnitude faster emulation while using minimal system resources. The memory requirements are very close to that of an original 8086 PC. Part of the emulation is implemented as BIOS code running on the 8086 side.

Also tinyxt provides an accurate UART emulation with carrier detection etc. making it possible to run vintage BBS software smoothly over IP. Experiments have been made using an original 8086 hardware with 16550 UART and 1980s telecommunications software. Xmodem transfer works reliably close to a line rate from Bitwoods over cellular internet.

Wednesday, 2023-11-15

Who's Better, Who's Best

A compilation album by THE WHO released in 1988.

My first proper introduction to THE WHO was this compilation album some time in the late 1980s or early 1990s. I was listening mostly to PINK FLOYD and LED ZEPPELIN, and wanted to check out some other legendary 1970s bands as well. I absolutely fell in love with the band's songs and sound, and kept playing this album over and over for weeks.

Some time after I was an aspiring record collector and a musical highbrow who thought that all compilations are crap and one should listen to the full original albums only. Which I did. And I after getting all their proper albums, I sold away this compilation...

While THE WHO made a couple pretty damn strong albums (notably Tommy, Quadrophenia and "Who's Next"), you still have to admit that they were a ``singles band'' as well (I wanted to say ``mostly'', but I don't want to upset PETE TOWNSHEND unnecessarily). And for such bands ``greatest hits'' compilations such as this are justified. Which is why I rebought this album couple decades after, and now listen it to probably more than any other THE WHO record. Not a single bad or filler song in there. And you have to respect the production, editing and mastering work on this compilation as well - it sounds a real solid piece of work and you won't even notice the recordings date from three different decades.

This is the very best of THE WHO.

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Send e-mail to Aaro Koskinen <aaro.koskinen@iki.fi> or leave a note at Bitwoods RBBS-PC.

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Last updated: 2024-08-05 22:36 (EEST)