[Info-vax] Valid disk types for SIMH?

[Paul Sture]

In article <7mvh5rF3gke5iU40 at mid.individual.net>,
 Bob Eager <rde42 at spamcop.net> wrote:

> On Mon, 23 Nov 2009 13:54:14 +0100, Paul Sture wrote:
> 
> > Now do INIT/ERASE in VMS and full allocation is achieved:
> > 
> > $ ls -l dua3.dsk
> > -rw-r--r--  1 simh  staff  5120000000 Nov 23 13:08 dua3.dsk $ ls -lh
> > dua3.dsk
> > -rw-r--r--  1 simh  staff   4.8G Nov 23 13:08 dua3.dsk
> 
> Does INIT/ERASE write nonzero values to every block? Don't have the 
> manual handy.

Yes it does. From V7.3 HELP INIT /ERASE

"If you specify the /ERASE qualifier, a DSE operation is performed
on the volume. For disk devices, the ERASE volume attribute is
set. In effect, each file on the volume is erased when it is
deleted."

I note that on V8.3 there are also /ERASE=INIT and /ERASE=DELETE, which 
allow you to specify the DSE operation and the volume attribute 
respectively, /ERSASE=(INIT,DELETE) being the default.

> If not, there will only be enough physical blocks allocated to cover the 
> nonzero blocks (on some file systems at least).

Now you have me wondering if what I am seeing is a feature of the OS X 
file system.

-- 
Paul Sture