Boot CD - The last LAP

Rod Smallwood RodSmallwood at
Thu Jun 14 18:12:49 CDT 2007

    This is all getting a bit complex. Its rather like a peculiar type
of English theatrical entertainment which happens around Christmas
called a Pantomime. One of the many strange customs is that under
direction from the stage one half of the audience shouts "Oh no it
isn't!!" and the other half replies "Oh yes it is!!" Don't ask me to
explain it any further. The rules of cricket and the plots in Chinese
opera are simpler.

So back to the original question:

   If I want to build a Linux system I go to a distribution site (one of
many), download an .iso image, burn it into a standard 600Mb CD, boot
the CD and create a system. No funny block sizes, no odd file extensions
and no special SCSI drives. So what can I not do this for VMS without
the pantomime? A step by step known to work checklist would be a start.



-----Original Message-----
From: cctech-bounces at
[mailto:cctech-bounces at] On Behalf Of Ethan Dicks
Sent: 14 June 2007 19:32
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Boot CD - The last LAP

On 6/14/07, Antonio Carlini <arcarlini at> wrote:
> Ethan Dicks wrote:
> > The joy of operating systems with enforced filename extensions.  :-P
> To be fair, this is Nero assuming or enforcing! I can usually override

> Windows' defaults.

Strictly speaking, yes... but extension rigidity is a Windows mentality.

> > That will be the key - to get whatever tool you use to write 
> > 512-byte blocks, not 2048-byte blocks.
> You cannot do this. The CD is always 2048 bytes per block. It is the 
> drive that pretends that instead of N 2K blocks you have 4*N 512 byte 
> blocks so it looks like a disk.

Ah... I had thought that the underlying filesystem was part of the
equation, not that the drive did all the work.

> This made life easier in the earlier days for the OpenVMS and Solaris 
> (and IRIX?) driver writers ... and threw the rest of us another bump 
> to trip over in the years to come!

I have worked with plenty of "starts up in 512-byte-block mode" issues
with old SCSI drives and Solaris - it does make boot code trivial
because you don't have to worry about the drive's block size.  It was
nice with later versions of boot ROMs and such that knew that they could
and should send a packet to tell the drive to switch to 512-byte-block
mode, removing the need for special models of drives with mode jumpers.

Honestly, though, I haven't had to worry about it (except when playing
Software Archaeologist) in a long time, but then I don't burn ODS disks


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