Imaging SCSI hard disks

[Paul Koning]

>>>>> "Ethan" == Ethan Dicks <dickset at amanda.spole.gov> writes:

 Ethan> On Wed, Sep 29, 2004 at 10:48:11PM -0400, Jerome H. Fine
 Ethan> wrote:
 >> HELP!!  Something seems to be missing.  Is SIMH being used with
 >> SCSI hard disk drives are are the SCSI hard disk drives first
 >> being copied to a hard disk file AFTER which SIMH does: ATTACH
 >> RQ0: hard_disk_file.DSK I don't know of any command that allows
 >> SIMH to ATTACH a raw SCSI hard drive like E11 allows.  What am I
 >> missing in this discussion?  PLEASE!!!

 Ethan> I have no idea how to do this with any version of Windows, but
 Ethan> UNIX/Linux/etc.  have always given you access to the raw disk.
 Ethan> In my case, the relevant command would resemble something
 Ethan> like...

 Ethan> ATTACH RQ0: /dev/sda

 Ethan> (where 'sd' is the driver, and 'a' is the controller).

 Ethan> This works with any and all emulators since to UNIX, unlike
 Ethan> Windows, everything is a file.  "Devices" are not special
 Ethan> entities to open()/close() calls, etc.

It's not quite that simple.

Most Unices (though not Linux) have two ways to look at disks, the
regular "block" device, and a "character"[sic] also called "raw".  To
do raw disk access you have to use the raw device.

Second, the application may need to know the size of the disk.  With a
file that's easy: seek to the end, and ask for the position.  While
devices are "files", the seek and position technique doesn't work
there, at least not on Linux when I was digging into this some years
ago.  You *can* usually find out how big a device is, but the means
are specific to each flavor of the OS.

    paul