BSD211 Tape building

Steven M. Schultz sms at
Mon Nov 27 17:09:29 AEST 1995

Hi -

> From: "Danny R. Brown" <sysyphus at>
> Greetings:
> The file size/# of records/block sizea aren't matching.

	I'm not sure what you mean by "not matching" - the sizes you list
	below are correct.  'boot' is 32462 bytes, 'disklabel' is 36191 bytes,
	'mkfs' is indeed 31727, and so on.

> Tape file    Docs- #records, size      PC        RT11disk blocks 
> 0 mtboot              1      512       512              1
>   boot               14      512      32462            64
> 1 disklabel    * 23@ 512 or 1024      36191            71
> 2 mkfs               28     1024      31727            62
> 3 restor             27     1024      34066            67
> 4 icheck             26     1024      31356            62
> * disklabel was quoted as two different bs in two different places.

	ARRGH!  That's a typo in the setup documents.  Sorry 'bout that.  I'll
	updated the master copies and post a patch in comp.bugs.2bsd soon.

	ALL of the executable programs (disklabel, icheck, mkfs, restor)
	must be blocked at 1024 bytes per record on the tape.

> I really think that my gunzipping is kosher- I do it in the PC

	Yep - it looks like the gunzip went ok - the byte sizes look correct.

> Anyway boot is too big or restor is to small, or something. Any ideas
> whatis going on here?

	You lost me there - what is too big or too small about them?  The
	record counts mentioned in the setup documents are examples - the
	counts were accurate at one time, but then if a bug was fixed or a
	feature added to boot or restor the number of records would change

	The various programs change size over time and the documents are not
	updated if the record sizes change a little bit.

	Oh - you need to have 2 copies of the 'mtboot' file at the front of
	the tape.  Why (I hear you ask)?  Some boot roms actually read the
	2nd copy!

	The format of a boot tape is:


	<TM> = Tape Mark.

	the first file (with mtboot,mtboot,boot) is blocked at 512 bytes, all
	the other executables are blocked at 1024 (ignore the typo in the 
	setup docs).

	Good Luck!

	Steven Schultz
	sms at

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