[Simh] Creating a blank (NOVA) disk image

[Clem Cole]

Stephen,

You did not ask how to create a larger file or if you want to know how to
format a DG disk for the OS like RDOS.   You also did not say what system
you are using to run simh.   The reality is that I would not think that
simh would care, as traditional C semantics on the 'create' system call
will make the entry for the disk in the file system, but until writes are
performed, the size is not determined.   The seek system call allows you to
seek beyond the end of the file and extended the size of the file as
needed.  I say this because simh, which is a C program, should behave that
way and thus not care.

If however, you think this is a problem, with any UNIX flavor (or if you
are using Win-10, WSL includes the standard UNIX utilities), if you type:
dd if=/dev/zero of=disk0.6103 bs=1M count=25
This will create a 25M file and zero fill it (according to the
http://simh.trailing-edge.com/nova.html the DG 6103 is a 25M file, you
could also make it larger or small as appropriate, but I think you get the
idea).

How to create a DG file system on it, will take booting the simh, Nova
emulator and running the DG utilities on that file after it was created.
ᐧ

On Mon, May 20, 2019 at 5:26 AM Stephen Merrony <merrony at gmail.com> wrote:

> Can someone remind me how to create a blank disk image file for use with
> SimH?
>
>
>
> I tried the following…
>
>
>
> set DKP0 6103
>
> attach -n DKP0 disk0.6103
>
>
>
> …but it just creates a zero-length file which is no use.
>
>
>
> Thanks,
>
>
>
> Steve
>
>
>
> *---*
>
> *Steve MERRONY*
>
>
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