Finally completed the 486DX2 system

The problems with the Toshiba CD-ROM drive were not related how the driver was loaded. I started having the very same occasional crashes. I had to accept that the drivers are buggy or there are some hardware incompatibilities.

No matter, I replaced the Toshiba drive with quad speed Mitsumi IDE CD-ROM drive. VIDE-CDD.SYS works perfectly with it since there were no transfer errors or crashes.

That also made the 486 system complete. It turned out to be quite nice. Here are the specs:

• Asus ISA-486SV2 motherboard + 16 MiB RAM
• Intel 486DX2 66 MHz
• Cirrus Logic CL-GD5428 based VLB graphics card with 2 MiB RAM
• Network card with XTIDE Universal BIOS ROM
• VLB multi I/O card (native support by XTIDE Universal BIOS)
• CF to IDE adapter with bracket (card can be easily removed)
• 6 GB Hitachi Microdrive
• Mitsumi quad speed IDE CD-ROM drive
• 3.5” Floppy Drive (quiet Panasonic)
• Sound Blaster 16 (CT2230) + Turtle Beach RIO (General Midi card with 4 MiB ROM)
• Temperature controlled power supply silenced with Nexus SP802512L-03 fan
• Barrel battery replaced with two AA batteries

I think it is a very good system for retro gaming. Of course my own 486 gaming system is even better in every way. Maybe I should write about it in my next post.

Problematic CD-ROM drivers

I haven't forgotten my blog. I've simply been too busy. Things are not going to get any better in the future. We (me, my wife and 6 month old baby) are moving to small 30m² apartment on November. The idea is to minimize expenses since we are planning to build our own house. But that takes time, usually more than planned, so we have to live long time in very small apartment. There is not enough room for my retro computers so I have to put them in storage for now. Best I can do is to keep my testing platform (basically a motherboard on a desk) so I can continue developing XTIDE Universal BIOS (I hope I have even a little bit time for that).

I mentioned a 486DX2/66 system previously. It is almost complete. It has been nice to learn FreeDOS with it although I had some problems with EMS managers. More about those once I've finished my testing.

Another problem have been a CD-ROM drive. I installed 32x Toshiba CD-ROM drive and it is jumpered as slave drive for primary IDE. Master drive is 6 GB Hitachi microdrive. I strongly recommend to connect CD-ROM drives to separate IDE channel when ever possible. This system only has primary IDE so it is not possible. I've usually used VIDE-CDD.SYS as generic CD-ROM driver. It has worked so far and it uses less memory than most other drivers. It did not detect this CD-ROM drive for some reason. All the other generic CD-ROM drivers I tried (including the UIDE that came with FreeDOS) did detect the drive but I constantly got read errors.

The Toshiba CD-ROM driver worked without read errors but it had completely different problem. It occasionally froze when loading it. When it didn't, everything worked fine. I managed to get few successful boots without freezing after I loaded the driver into low memory instead of high. The problem is not related to FreeDOS but affects MS-DOS as well. I'll need to do more testing to see if loading low is a working solution or was I simply lucky. I can't think of any reason why loading high would cause any problems unless

I'd like to know why this CD-ROM drive requires Toshiba drivers. It should be ATAPI drive and so it should work with generic ATAPI drivers but it did not.