Re: Strange IIgs error

[Phoenyx <quazar@dcnet2000.com>]

> Just for reference P8, the bootable file formally known as ProDOS before
> GS/OS came out should be about 35 blocks large... if you have a 4 or 5
> block file it is soime GS/OS boot code.
>
> So for a standard //e, //c, IIgs bootable ProDOS disk you need the 35
> block PRODOS file and Basic.System

Technically, no. This is only one of many possibilities. :-)

The standard bootable Prodos 8 disk should have a file named PRODOS with a
file type of SYS ($ff) which must begin with 6502 executable code. This
file gets loaded by the 6502 code stored in the disk block $00. Note,
block $01 is reserved for this also, but seldom used.

In turn, Prodos looks for and executes the first file it finds with a file
type of SYS that has a file name ending with .system (and should also hold
65(c)02 executable code.)

It is quite possible to make your own bootable disk with any code you
want. Whether this is practical is a different matter. Theoretically,
you can replace the boot block code and supply your own routines which
may (or may not?) be an OS in it's own right. Some early copy protected
disks used similar methods as part of their protection scheme.

As an example, the Hyper C system had a version which included it own OS
called CDOS. This system used block sizes of 1024 bytes but the bootstrap
still resides in the first 'block' due to hardware requirements.

-- 

Thank you for your time and interest. I hope it was helpful
or at least interesting.

Phoenyx,

Apple2 user since March 1984

Links to Phoenyx's pages:
preferred..... http://zip.to/Phoenyx_A2
alternate..... http://www.tinyangeldesigns.com/Apple2