Title:		HOWTO_SIMH_bootable_1MB_hdsk

File:		HOWTO_SIMH_bootable_1MB.txt

Author:		Michael Rychlik

Date:		01-09-2009


The aim here is to make a bootable 1Mb disk image of 254 tracks, 32 sectors per track
and 128 bytes per sector for use as an hdsk under SIMH AltairZ0 or ZiCog/TriBlade
Z80 emulation.

This is the same geometry as the SIMH Altair floppy disk but 128 bytes sectors not 137.

Let the disk image to be created be called new.img

These are the steps:

1) Start with no file in the altairz80 directory called new.img

2) In the SIMH configuration file attach the non-existant new.dsk as hdsk1
and specify its geometry with something like the following:

attach hdsk1 new.dsk
set    hdsk1 geom=254/32/128


3) Start SIMH using that configuration and format the new.dsk which will be
drive j: in this example:

A> XFORMAT J:

N.B. XFORMAT will report formating a disk with 2048 tracks but we only
want (and get) 254 tracks. The LS command will also indicate 2048 tracks.
Ignore this.

4) IMPORTANT Do not exit SIMH here otherwise the next steps will fail later.

5) Lay down the boot sectors of new.dsk

A> BOOTGEN CPMBOOT.COM J:

6) Copy whatever files are required onto the new boot disk:

A> PIP J:=*.*

7) Now exit SIMH and start it again. There will be warning messages from SIMH like:

HDSK1: WARNING: Unsupported disk capacity, assuming HDSK type with capacity 1040KB.
HDSK1: WARNING: Forcing WRTLCK.
HDSK1: WARNING: Fixing geometry.

and LS J: will report 2048  tracks !!

Ignore this, the disk is done but it is un-writable by SIMH anymore.

8) Check that this new disk is bootable by changing the SIMH config as:

boot hdsk1

and restarting SIMH.


Done.


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