From:	SMTP%"RELAY-INFO-VAX@CRVAX.SRI.COM" 22-JAN-1994 19:39:03.93
To:	EVERHART
CC:	
Subj:	Re: bootstrap for MicroVAX II

X-Newsgroups: comp.sys.dec,comp.os.vms
From: gbcacm@ccs.neu.edu (Peter Sherwood)
Subject: Re: bootstrap for MicroVAX II
Message-ID: <1994Jan22.220941.196@random.ccs.northeastern.edu>
Sender: news@random.ccs.northeastern.edu
Nntp-Posting-Host: denali.ccs.neu.edu
Organization: College of CS, Northeastern University
Date: Sat, 22 Jan 1994 22:09:41 GMT
Lines: 40
To: Info-VAX@CRVAX.SRI.COM
X-Gateway-Source-Info: USENET

In article <2hnct2$ejl@nz12.rz.uni-karlsruhe.de> bertram@ifib1.ifib.uni-karlsruhe.de (Bertram Barth) writes:
>i'm trying to create a boot-block for a MicroVAX II, but i'm missing
>a few informations.
>- what is the exact location of this table in LBN 0 ?
>- what and where are the fields in this table ?
>- are there any other restrictions in the boot-block (magic bytes at certain
>  locations, special instructions, etc.) ?
>- where is the entry-point of the secondary boot image ? (first byte ?)

OFFSET	CONTENTS
0	anything
2	n=offset in words to identification area
3	1
4	logical block number (word swapped) of the secondary image
[Identification area]
2n	18 hex
2n+1	0
2n+2	anything
2n+3	1s' complement of sum of previous 3 bytes
2n+4	0
2n+5	1=single-sided  81=double-sided volumes
2n+6	anything
2n+8	longword; size in blocks of secondary image
2n+12	longword; load offset (usually 0) from the default load addr of
		secondary bootstrap
2n+16	longword; byte offset into secondary image to start execution
2n+20	longword; sum of previous 3 longwords


>- in which books/documentation should i look to get more information ?

All the CPU User's Guides have this info; above is from KA620-A CPU Module
User's Guide, DEC p/n EK-KA520-UG-001 (1986).

-----------------------------------------------------------------------------
Peter Sherwood
(617) 332-8880 (voice)
(617) 332-1675 (fax)
gbcacm@ccs.neu.edu
-----------------------------------------------------------------------------