Imaging SCSI hard disks

From: Zane H. Healy <>
Date: Wed Sep 1 00:51:26 2004

>>What I've not attempted to do is dd a disk image back to a SCSI HD. It's on
>>my list of things to try, but who knows what decade I'll finally find the
> I haven't done this on a PDP-11, but have done it with SCO Unix,
>Linux, and FreeBSD drives. It's all geometry. I do know that BSD
>v2 sets partitions on cylinder boundaries, so the principles should
>be the same as in later platforms.
> You need a target disk with the same head/sector geometry as the
>source. The number of cylinders is a lot less critical, as long as
>the target isn't smaller than the source.
> You can actually get away with using an unmatched target as long
>as fsck never runs. :)
> I dunno about other OS disks. The little I know about RT-11's
>filesystem implies that most any old disk should work.

My idea is actually to first dd the HD to a disk image, then prep
that disk image under SIMH or E11. Copy the data I want on the HD to
the image using the emulator, and then dd it back to the HD.
Logically it should work just fine. With RT-11, you shouldn't even
need to dd the HD to a disk image, just create whatever size disk
image and dd it out there. The other OS's would be a bit more picky.
It should be a good way to get a large amount of data onto a PDP-11,
however, I've yet to actually have a need to attempt it (I've just
used Ethernet or CD-R to get data on).


| Zane H. Healy                    | UNIX Systems Administrator |
| (primary)    | OpenVMS Enthusiast         |
|                                  | Classic Computer Collector |
|     Empire of the Petal Throne and Traveller Role Playing,    |
|          PDP-10 Emulation and Zane's Computer Museum.         |
|                     |
Received on Wed Sep 01 2004 - 00:51:26 BST

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