kikendo wrote on 2020-06-11, 14:49:
I'm resurrecting a Gateway 2000 386SX/25 and I would like to get a hard drive for it since the one it came with (~80MB) is dead. […]
I'm resurrecting a Gateway 2000 386SX/25 and I would like to get a hard drive for it since the one it came with (~80MB) is dead.
I read about the several BIOS limits for IDE devices, but what I didn't find is how to recognize which BIOS I have in order to be able to buy the largest replacement I possibly can.
The machine is from ~1991 and my only guess is that a 512MB one would be fine, but if I can put in more it'd be great, since 512MB will not hold that much when I start installing CD-ROM games.
BIOS chip is marked as: Quadtel 286/SX 120594
Thanks in advance for any info you can provide!
Hi! And congrats for your 100. posting! 😁
Well, I don't know for sure. The "problem" is CHS limit / max. support via normal int13h.
Some BIOSes allowed higher values for normal int13h, but were causing compatibility issues.
That's why extended int13h was introduced (with PS/2 line of PCs ?), but DOS doesn't use that extended int13h..
Edit: Related to this might be the 4096 cylinder limit.
"Summary: Some BIOS-- developed before the second half of 1996-- limited the physical drive
Cylinders to a 12 bit binary number, which supports a maximum of 4096 Cylinders or Tracks. (CMOS values 0 to 4095)"
So it's hard to say. If you like to use higher capacity drives, don't worry.. The ~504MB limit is not a hardware limit.
Just use XTIDE BIOS on a network card or use a DDO (Dynamic Drive Overlay) and the IDE ports on you 286/386 can support 8GB just fine.
Anyway, if you like to find out the HDD limit, just run FDISk and see how much it will try to allocate for your drive.
If something goes wrong, you can clear the card / HDD using S0Kill.
PS: DOS 5+ can use more than 2GB (per partition) on FAT16 if patched. In Virtual PC, for example, the normal int13h allows for more than ~504MB. 😉
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Edit: I forgot to mention.. You can use "fake CHS" values just fine. That's how things were done before LBA.
Just use a combination of cylinders/heads/sectors that's within the limits of your HDD.
As long as you don't exceed the maximum capacity of your HDD, everything will be fine.
My father and me did this on my 286 in the 90s.
HDD was an 80MB Conner drive, but CMOS setup had a 40MB limit (no type 47).
If you're afraid of data corruption, simply run CheckIt! (v3 or v4) and let it do the HDD test.
If no errors show up, things should be fine! 😁
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