2.88MB images

[Rather long]

The following problem appeared when I started to play
with bootable CDs and is not solved yet.

It appeared 1.44MB is not enough. I need 2.88MB.
And it has to be FreeDOS bootable (kernel.sys,
command.com, you know).

Since I don't have 2.88MB floppy, I can't simply
FORMAT A:, SYS A:, RAREAD A:

Ideas that came to my head:

1. Use popular XMS disks like BITDISK, XMSDISK.EXE.
2. Use little-known XMSDISK.COM.
3a. FORMAT / SYS should work on images.
3b. New XMSDISK (based on BITDISK) with structure of
    real diskette.

Ad. 1. Use popular XMS disks like BITDISK, XMSDISK.EXE.
=======================================================
But:
1.1. They assign letters like D:, E:, F:, so
     RAREAD doesn't work on them.
1.2. DSKIMAGE doesn't work, too
1.3. Even if somehow (how?) I managed to dump to image,
     would it be usable by rawrite?

Ad. 2. Use little-known XMSDISK.COM.
====================================
It's XMS disk but assigns A: or B: letters.
When enabled you have `virtual diskette' in XMS memory.
When disbled you have an access to a real floppy.

After enabling, you must use FORMAT A:/B: to format
a virtual diskette. (and FORMAT recognizes it as
a real floppy disk, not as a HDD).
You CAN use RAREAD to dump to image.

But:
2.1. There is no source.
2.2. XMSDISK.COM supports only 360,1.2,720 and 1.44
     but not 2.88MB disks.

First idea was to make a quick hack to force XMSDISK.COM
to support 2.88MB.

But:
2.3. You must have proper settings in BIOS.
     I.e. if you want XMSDISK.COM virtual diskette to
     behave as 720kb, you must set in BIOS A:/B: floppy
     as 720kb 3.5"

If you use noname PCs, it should work.

But recently I've played with Fujitsu Lifebook E350.
I love these brand-known notebooks (joking :) ).
Their BIOSes don't give too much freedom for users
(err, sounds like m$).

In my both 486 and Celeron I can set in BIOS A: as 2.88,
but in Lifebook there is rather info than option:
Floppy-1.44MB and no way to change it :(

Ad. 3a. FORMAT / SYS should work on images.
===========================================
If the following commands work:

FORMAT /I=image_file
SYS /I=image_file

I could create bootable 2.88MB images even
on brand-known PCs.

Quick look-through FORMAT source code
gave me that we can differientate between
real and virtual diskette inside function Drive_IO.
I'm not sure if Flush DOS Disk buffers in function
Create_File_System should be left as are, or removed.
SYS is another problem - I lost myself in source ;).


Ad. 3b. New XMSDISK (based on BITDISK) with structure
        of real diskette.
=====================================================
Write 2 progs: XMD disk and DUMPER.

Write XMS disk (or rather modified version of BITDISK)
with proper structure of diskette. It means, that after
running with i.e.:

DEVICE=c:\BLE.EXE /F:2880

or

DEVICE=c:\BLE.EXE /T:80 /S:36

you dump it to image, and run:

FC /B VDI RDI

you should get "No differences",

where:
VDI = Virtual diskette image
RDI = Real diskette image (taken frm new, fresh
      diskette, just from your shop)

Of course, you should be able to resize
image after installing in CONFIG.SYS. (BITDISK allows
such an activity, today).

DUMPER is simply a prog that will dump XMSdisk to image
usable by RAWRITE.



Enough. My first choice: 3a.

Chris




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