[syslinux] Remote HD boot?

myfj1200 at netzero.net myfj1200 at netzero.net
Tue Jan 18 18:42:38 PST 2005

>>> My question would be: Is it possible to boot a diskless client PC
>>>  with Complete hard disk images? or even better hard disk 
>>> contents mounted on the server?
>> That depends. Generally: Yes, Memdisk can emulate Harddisk Images 
>> from Ram. (AFAIK) Not from Network.
> I have attempted this with smaller MS loads 100-500MB Fat16/32 
> Dos/Win9x Builds with no luck.  It runs through the whole boot 
> process up to the infamous "dots"  it will blow about 1 page of 
> on the screen until all network traffic stops as do the dots across 
> the screen...

So far so good.

> Is this a likely RAM issue or am I just creating the image wrong?

Most likely creating the image wrong. Of course you should have enough
memory for the image to fit in... I've booted successfully booted 200MB
DOS images via PXELinux. (I didn't create them from a physical Hard
Drive but by "dd if=/dev/zero of=disk.img bs=512 count=x".)

??Out of curiosity how else would you make a 200MB hard disk image?

For trying it out, you might want to use Syslinux load the Image into
RAM from a local Harddrive (to speed up trying). It can start memdisk
the same way as PXELINUX does...

??note:  I don't know how to do this. 
??Would this be with a Linux recovery disk boot?

> I have been using syntax like : dd if=/hard disk mount of=disk.img

If you use
dd if=/dev/hda of=/home/user/disk.img it should work - if /dev/hda is
the Harddisk you want to Image.

The Disk Image has to contain the MBR with partition table and the
partition itself (/dev/hda1 wouldn't work, since its just the partition)

Maybe you need to supply Memdisk with the right Drive geometry for the

ok..I've been working with this for a few days and still have yet to nail this one...

The server still seems to be working properly booting with PXELINUX v3.01  (also tested with 3.07 on a test box).

I took this one step further and after much hunting was able to locate a functional 100MB hard-disk with the specs listed(1024/17/12).  In order to keep this simple for diagnostic purposes I used a Windows 98 EBD to make the whole 100MB drive 1 Fat16 partition (also tried fat32) Formatted this with the /S (system disk) command then proceeded to copy the basic utils and about 60MB of fluff.  This drive locally in a CPU boots normally to a C:> prompt.
I then from lack of knowing a better way took the 100MB drive out and stuck in in on the second hard disk cable in place of the CD-ROM on a box running RH Linux V9 Kernel V2.4 as a Workstation...
In a Terminal window then proceeded to type:
dd if=/dev/hdc of=/tftpboot/full.img
dd if=/dev/hdc of=/tftpboot/full.img bs=512
and many varieties of this.  
using the boot options Kernel memdisk initrd=full.img 
It will still give me about 3/4 a screen of dots along with all the boot time specs which lists the Drive geometry properly then it comes up with a Disk I/O error Insert another disk message. (not verbatim)
  I've read every document I could find in regards to SYSLINUX and it's derivitives to no avail...
Any more suggestions? 

     Thanks again,  Joe...

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