per
Veteran Member
I'm in a bit of a problem right now. I want to try to set up DOS 2.11 on a harddrive in a non-PC computer I have, (after the old disk crashed), but the standard floppy release doesn't have a device driver for the harddisk. I do have a backup of the original IO.SYS with an internal driver for the harddisk, but I have never been able to get that to boot from floppy. I have a format utility, but it's of no use unless the harddrive is mapped to a drive letter.
So my best bet right now is to manually piece together some kind of FAT12 implementation, and write it to the drive sector by sector.
Layout overview:
1 sector reserved for boot (allthough it's not used; DOS is loaded from harddisk with a program in a simpler OS)
16 sectors of FAT, 8 tables if I'm not mistaken.
32 sectors directory
The remaining 10355 sectors make up the data area.
The loader blindly assumes IO.SYS and MSDOS.SYS are in the start of the data area if their entries are in the directory table. What I need to do is just reconstruct a good enough implementation such that MSDOS.SYS will be able to load and run COMMAND.COM. From there I should be able to run the proper harddrive formatting tool.
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I have also tried to look into patching IO.SYS. There are not that many differences between the floppy and the HDD version of this file, but for some reason the HDD version will utterly fail to load if you attempt to boot it from diskette. If I could get it to map the HDD as drive B or C instead of A on boot, then it would problably work.
So my best bet right now is to manually piece together some kind of FAT12 implementation, and write it to the drive sector by sector.
Layout overview:
1 sector reserved for boot (allthough it's not used; DOS is loaded from harddisk with a program in a simpler OS)
16 sectors of FAT, 8 tables if I'm not mistaken.
32 sectors directory
The remaining 10355 sectors make up the data area.
The loader blindly assumes IO.SYS and MSDOS.SYS are in the start of the data area if their entries are in the directory table. What I need to do is just reconstruct a good enough implementation such that MSDOS.SYS will be able to load and run COMMAND.COM. From there I should be able to run the proper harddrive formatting tool.
-------
I have also tried to look into patching IO.SYS. There are not that many differences between the floppy and the HDD version of this file, but for some reason the HDD version will utterly fail to load if you attempt to boot it from diskette. If I could get it to map the HDD as drive B or C instead of A on boot, then it would problably work.