[comp.sys.mac.programmer] SCSI help answering some common questions

Eliot.Henry@samba.acs.unc.edu (BBS Account) (09/01/90)

k most people who have sent me mail have had a few questions.
(argh i don't know vi well)

I repeat: Ok, most people who sent me provate mail had a few questions

1) Am i writing a virus?

	No, the program is needed to securely erase hard drives at the company where i work (sorry they won't allow me to say where)

2) Why don't you use an existing package?

	I need to erase to govt specs and #2 the company wants me to create it!

So living within those guidlines any help would be greatly appreciated!
Anyone with some source code examples in C or pascal?
(AND for the last time people I have volume 1-5 of inside mac and read the
sections!)  I don't know what format the section pointed to by the call should
vbe in. Should it be a series of bytes composed of commands. If so how will
the call know when it has reached my last command. Or do i give one call for
each command?

thanks again

minow@mountn.dec.com (Martin Minow) (09/04/90)

In article <976@beguine.UUCP> Eliot.Henry@samba.acs.unc.edu (BBS Account)
asks about programming "raw" scsi commands.

If you want to call the Scsi Manager directly, you will need at least
the following documents:

-- Inside Mac V4 and V5 for the Scsi Manager documentation.
-- Ansi SCSI-II draft specification (moderately expensive, order from
   Global Documents).  This is a tough-reading but essential reference
   to scsi devices.  (The spec is very well done.)
-- The hardware/firmware manuals for the devices you need to access.
-- (Recommended) The SEdit package in one of the developer's disk -- you
   should read the documentation for some important hints.
-- (Recommended when trouble strikes): A scsi bus analyser.

You call the Scsi Manager by providing the following information:

-- the bus ID of the device you need to access.
-- the SCSI command block (see the spec/device manual for the format).
-- if the command does a data transfer (read or write), you also need
   a transfer information block to describe the data buffer.

Eliot's specific need is to erase disks to "government standards."  I would
recommend that he use one of the commercially available products that were
written specifically to meet those standards.

Martin Minow
minow@bolt.enet.dec.com