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Best hard drive alternative for a 386 machine

C

chriswareham

New Member
Joined
Feb 13, 2020
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Location
London, UK
Hi folks,

I'm restoring a Tandon 386 based PC - so far I've recapped the power supply, replaced the Rayovac CMOS battery, cleaned and lubed the floppy drives. It currently has 640KB of RAM on the motherboard and a pair of 1MB sticks in two of the four SIMM slots, but I've bought four 4MB sticks from eBay that are on their way to me.

tandon1.jpg


tandon2.jpg


tandon3.jpg


tandon4.jpg


Judging by the label on the rear, the 5.25" floppy drive was a later addition. It also has a Seagate ST1144a hard drive, which appears to be 130MB in capacity. However, despite playing around with the BIOS I can only get the machine to see 40MB of the drive. My goal with the machine is to run the first version of Visual C++ on it for some retro programming on original vintage hardware, so I'd like to have some more disk space. In the BIOS there is an option to select either MFM or RLL drive, and then a "drive type" which is a number from 1 to 47. 1 allows the machine to see 10MB and 47 allows it to see 40MB. Any suggestions on how to get it to see as much of the Seagate drive as possible would be seriously appreciated!

Failing that, would an XT-IDE card be a good way to get more disk capacity? I have one in my IBM 5150 - the machine that got me hooked on retro PCs. Or are there better options for a 386 class machine that already supports IDE?

Chris
 
chriswareham said:
Hi folks,

I'm restoring a Tandon 386 based PC
Click to expand...

Nice looking machine. Clean and slimline. Have you had the chance to see if it boots?

chriswareham said:
Failing that, would an XT-IDE card be a good way to get more disk capacity? I have one in my IBM 5150 - the machine that got me hooked on retro PCs. Or are there better options for a 386 class machine that already supports IDE?

Chris
Click to expand...

Most often a DOM (Disk-On-Module) or CF Adapter gives a solid-state solution to an older (286-486 class) machine. The trick is finding DOM's small enough (unless you don't care about wasted space beyond the OS limit) or CF Adapters that actually work properly as a replacement HDD. You could also use an IDE drive with a DDO (Disk Drive Overlay) but then it'd be subject to failure the same as any other IDE drive (and DOM's and CF drives have a lifespan as well).

https://www.vogons.org/viewtopic.php?t=58558
https://www.daniel-boehmer.de/thinkpad-cf/
https://en.wikipedia.org/wiki/Dynamic_drive_overlay
 
IMO if you have a working mechanical drive, keep it. Type 47 in most setup programs is a "user type" meaning you can directly enter the CHS values for the disk. See if you can pick 47 and then key in 1024/14/17 for C/H/S. Barring that, using the XT-IDE Universal BIOS (just the ROM, not a physical XTIDE card) will also allow you to get the full capacity.
 
Many thanks for the replies!

I installed a fresh copy of MS DOS 6.22 and Windows 3.11 to the 40MB of the hard drive that the machine can see. It boots, and Windows runs very well with the Oak Technology card that the machine came with. The motherboard didn't seem to need any electrolytic caps changed, as I could see no signs of bulging or leaking. The PSU looked fine as well, but I still prefer to recap older power supplies as a precaution. It;s a nicely built machine with the CPU itself on a daughterboard, and I suspect that the motherboard was used across a both 386 and 486 models.

Interesting reading at those links T-R-A posted, and I suspect I'll go the XT-IDE Universal BIOS route - selecting drive type 47 in the BIOS doesn't give me any options to set the CHS values, so it seems to be another hardwired set of values. I'm also going to be installing a Sound Blaster 16 card. I like programming MIDI applications for all kinds of machines, so I'll be using the MPU 401 support for that - the SB16 only supports the "dumb" MPU 401, but that's fine for my purposes.
 
There are also two other types of adapters that I have used:

- IDE-to-SD adapters
- IDE-to-mSATA adapters

The IDE to SD adapters are much cheaper, as SD cards are now much cheaper than CF. And, the IDE-to-mSATA adapters work with real SSDs, giving the benefits of wear leveling. Additionally, small mSATA SSDs are quite inexpensive.

- Alex
 
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