[syslinux] Creating HD Boot Images

[Christian Marg]

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Hi...

SysLinux User wrote:

> I have been trying to track down information on building HD boot images
> for ISOLINUX and MEMDISK, and so far, haven't had a whole lot of luck.

The question was already asked. A request to add this info to a FAQ or
the Webpages seems not to be implemented yet.

- -------- Original Message --------
Subject: [Fwd: Re: [syslinux] Disk images and syslinux (OT?)] was:
Creating hard disk image
Date: Sun, 06 Apr 2003 11:57:32 +0200
From: Christian Marg <christian.marg at tu-clausthal.de>

Hello

Take a look at these Messages (see below) that were previously on
Syslinux, or search on http://www.zytor.com/pipermail/syslinux for your
answer. (DL the full archive and grep, if HPA hasn't built in some
search function)

bye
Christian


- - ---------------------------------------
Subject: Re: [syslinux] Disk images and syslinux (OT?)
From: Christian Marg <christian.marg at tu-clausthal.de>
Date: Fri, 21 Mar 2003 12:22:24 +0100
To: syslinux at zytor.com

Hello...

Karri Puumanen wrote:

I have succesfully used bootable 1.44 and 2.88 images with
syslinux/memdisk. No problemo there. The challenge is how to create a
bootable 5-15 MB disk image with correct geometry, MBR, boot sector,
active bit  etc.

Having instructions/tools to do such image would make possible for
example intgrating all IBM ServeRAID firmware update disks (3 in total)
into one image.


Well, Just take your calculator:

5Mb*1024*1024/512=10240 Blocks each 512 bytes (the sectors)
Now lets go for the "Geometry"
10240Sectors /63 Sectors per Cylinder = 162+decimals
Round it up and  divide 163 by the number of  "Heads" you want the Image
to have.
You could take 1 or two, just remember the Cylinder count has to be < 1024
Now I've got the Geometry 82Cylinders/2Heads/63Sectors. Multiply all
Numbers together to get the Sector count you need for this geometry
(remember we rounded up)  and you get 10332 Sectors total.
Then you take your dd if=/dev/zero of=diskimage bs=512 count=10332 et
voila your diskimage.
Partitioning is next: I think I used cfdisk, which has an option to give
the drive geometry on the cmdline. You give it the Geometry and the path
to the file and partition your disk image.
If that doesn't work, you need to attach the file to a loop device via
"losetup" (I don't remember, if  fdisk was working on the file or only
on devices)

It gets tricky, if you want to have, eg. MSDOS on that "drive": I used
Dosemu to boot a floppy image of Msdos and somehow tricked Dosemu to
have my "Harddisk" by bypassing all configuration files, then using "sys
a: c:" to get the image bootable. Perhaps the process is easier for
freedos...

If there are any errors, please correct me, because I did this some time
ago and don't remember every step of it...
bye
Christian



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Subject: Re: [syslinux] Disk images and syslinux
From: "H. Peter Anvin" <hpa at zytor.com>
Date: Fri, 21 Mar 2003 10:24:39 -0800

Josef Siemes wrote:
Hi,

"Karri Puumanen" <karri.puumanen at mainframe.fi> schrieb am 21.03.03 09:01:45:

I have succesfully used bootable 1.44 and 2.88 images with
syslinux/memdisk. No problemo there. The challenge is how to create a
bootable 5-15 MB disk image with correct geometry, MBR, boot sector,
active bit  etc.

I can't help much with that. Someone suggested to use dosemu for this,
with fdisk on a
loopback mounted file - but I didn't try that.


FWIW, the mkdiskimage tool that comes with SYSLINUX can generate blank
HD images, including ones in DOSEMU format.  MEMDISK can use DOSEMU
format directly nowadays.

    -hpa
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