red_avatar wrote on 2022-01-11, 10:44:I've done so much searching to find the solution to getting a larger drive that I pretty much discovered all the downsides and l […]
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I've done so much searching to find the solution to getting a larger drive that I pretty much discovered all the downsides and limitations (I hope)
For example: the C drive which contains the OS has to be 8GB or less because the BIOS needs full access to the drive on boot. If you go above 8GB and vital system files fall outside of the 8GB area, it will cause major problems.
The crashing and corruption you mention is mostly a problem with DDO (dynamic drive overlays) which change the MBR to basically bypass the BIOS. My previous drive got corrupted because I used a DDO which is why I now refuse to use one any longer. Windows itself has its own Int 13h system and ignores the BIOS so as long as you can get inside Windows, you can run a Scandisk to fix the D drive if needed. The C drive is perfectly "normal" for the BIOS (it doesn't even see the D partition)
Windows itself can handle much larger drives than 8GB but you're still limited to your system - in my system, the maximum is 32GB. I tested this in the past: when I go over 32GB, it starts writing garbage and files get corrupted. Later systems can go up to 127GB which is why my Pentium III has a 120GB SSD.
Basically, my current setup should be perfect:
- set the C (boot) drive to 8GB which the BIOS can boot from and access
- set the D drive to 22GB and use it for Windows software & media files
- use the C drive for all DOS applications
- hide the D drive in DOS so the PC does not lock up trying to access it
I will also make a backup of the drive using HDD Raw Copy which is excellent for backing up drives completely regardless of their content.
It depends on the DDO. In my case, my ancient PC's BIOS can't properly access disks without DDO (Windows will refuse to install). Only when using a DDO would I be able to install Windows and use the entire disk.
As for corruption, I'm not sure what happened, but from what I remember, trying to boot floppy/CDs outside DDO is unsafe and could indeed cause corruption especially when using disk utilities.
By booting outside DDO I mean booting a floppy/CD directly (by setting floppy/CD first in the boot sequence), before DDO gets loaded (which expects the DDO-installed hard disk to be first in the boot sequence). Booting floppy inside DDO (by using the key combination for floppy boot shown in the DDO prompt after it's loaded) is usually safe.
PS: I think DDO did so by overriding certain "broken" BIOS calls (like INT13) with its own, and the overridden calls carry over to the OSes booted afterwards (so that any further operations on the disk would work correctly). The currently active INT13 (and other BIOS calls) can still affect things even after Windows booted. In my other case (which happened on a 865-based motherboard), the data in my 3TB drive got partially corrupted when I tried to back up stuffs from other drives to there and the corruption happened after data got written to spaces past 2TB. At that time, the BIOS overflowed when reporting total sectors count and showed the disk as being ~960GB, but the OSes I was using could fully recognize the entire 3TB and could even quickformat it without issues.
Also, utilities such as Hard Disk Sentinel can notice such discrepancy between sizes reported by BIOS and by the OS, and warned me about potential data loss back then, but I didn't pay serious attention to it until I learned my lesson the hard way.
