Gixxxer wrote: Also, you don't need to make your own FAT 16 partition, FDISK will just ignore anything beyond 8GB. Also a single 8GB partition in FAT16 is incorrect for DOS use. Biggest partition possible in DOS 4-7.0 is 2GB, but you can make 4 of them to have access to 8GB, so you'll need to re partition your disk.
Also interesting thing i noted. Dos 6.22 installer made a 4gb partition not multiple 2gb partitions.
Interesting, indeed. Under certain circumstances (i.e. oddball BIOS, patched), DOS 5/6 at its core can handle between 3GB and 4GB for each FAT16 partition.
It mainly depends on the BIOS, however. Also, a lot of third party utilites don't support that.
See screenshot -> Re: Intel VS440FX refuses to boot DOS 6.22 from detected SSD
PS: Older OEM DOSes and clones had variable sector sizes (default=512 Bytes per sector),
which made it possible to break the barriers of the time (original FAT16 had a 32MB limit on DOS 3.x or so).
Edit: Ok, I'm not sure if I can explain that well, but in simple words, for example,
it's possible to alter DOS 5/6's system files to handle more than 1024 cylinders.
This requires a BIOS that reports more than 1024 cylinders via int13h (not the extended one).
Even though IBM's AT BIOS had that limit by default (10bits only), later AT-Bus hard disks usually didn't expose that limit (~4096cyl).
Now, some clone BIOSes could handle ~4095 cylinders -via classic int13h- by using 2 more bits in the DH register (12bits),
which can be taken advantage of to let DOS see more than 1024 cylinders (beware cyl. 1023 is a diagnostic cylinder).
The BIOS inside of Virtual PC 200x falls into this category, for example.
Other BIOSes may limit the int13h in order to maintain maximum copatibility with mainstream OSes.
Another requirement is that the BIOS uses the fixed disk parameters blocks int41h/int46h, respectively, for hard disk #0 and #1.
That's required for FDISK. Once FDISK is modified, it can use these two ints instead of int13h, function 08 to retrieve the maximum cylinder count.
(If it is misbehaving for what ever reason, I imagine it could be encouraged to do the same without modification.)
DOS itelf is quite easy to please. During boot-up it looks for a partitio table with a partition that's within a length of 1024 cylinders
and once found, uses that and calculates the end of it by using the 32-Bit sector count in the partition table.
Anyway, I hope got that right. 😅
The bottom line is: FDISK and BIOS are the main cause that limit DOS5/6 to 2GB partitions.
DOS may or may not beable to handle bigger partitions, depending on the system it is being run on-
That being said, I'm curious what DOS4 is capable of, once tweaked. 😀
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
//My video channel//