Subject: A Real O/S for DECmate III?

From: [email-masked] (jonathan_boswell)
Date: Wed, 12 Oct 1994 19:36:31 GMT

I just finished reading the most excellent FAQs on the PDP-8.  What a blast
from  the past!  But here's my question.  Is there any operating system out
there which is runnable on my DECmate IIIs, aside from the WPS?  Ideally
these would be available for anonymous ftp, but I'm dubious of the many
compatibility problems.  I'm also dubious of the method for getting a bootable
binary onto floppy disk.

Jonathan Boswell
FDA/CDRH

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From: [email-masked] (Charles Lasner)
Date: 17 Oct 1994 16:22:37 GMT

In article <[email-masked]>,
>compatibility problems.  I'm also dubious of the method for getting a bootable

As many readers of alt.sys.pdp8 already know, the sunsite.unc.edu archive 
contains a number of standard distribution disks for DECmates II, III, 
III+ already.  The currently supported format is PC TELEDISK image format 
embedded within .ZIP files along with a nice ASCII text label file for 
the diskette itself.  (The label format assumes fairly standard address 
labels are used, etc.)

Thus, what is needed is a PC with 5.25" high-density diskette (preferably 
TEAC FD55GFR) and the TELEDISK program, and PKZ204G.EXE PKUNZIP, and 
whatever net.means to get the file to said PC, etc.

Some of the provided disks are suitable for the DM III, but will not 
specifically run on it as provided!  The reason is that the diskettes 
predate the DM III and must be updated using the System Test Diskette 
Version 4.5, one of the provided diskettes.  One of the disk files is a 
copy of a personal working diskette of OS/278 with Kermit-12 and other 
non-release files on it.  This particular disk has had the slushware 
update and will boot immediately as provided on any of the three 
machines, etc.  Additionally, it includes a disk copying program that can 
be used immediately, something especially useful when getting started, etc.

Every one of the files has been "double-blind" tested.  This means that 
the following round-about process has been performed:

1)	The original diskette is copied on a DECmate II onto another 
diskette that has been previously formatted for RX50 on a specific target 
PC drive using RAINDOS or 22DISK, etc.  This is to ensure that TELEDISK 
has no problems reading the disk.  We have found that strange anomalies 
on RX50's from DEC are occasionally picked up by TELEDISK.  This extra 
step avoids that problem, and also the problem of misreading existent 
sectors some users report with TELEDISK, etc.

2)	The target diskette is brought back to the designated PC (where 
it had been formatted earlier) and a TELEDISK image file is created using 
the so-called "normal" compression mode.  (In this mode, only zeroes are 
compressed.  TELEDISK full compression runs too slow, and PKZIP generally 
does a better job anyway!)

3)	The image file is combined with the label file into a PKZIP 204G 
.ZIP file.

4)	The .ZIP file is sent to the net and ultimately to the archive 
area on sunste.unc.edu.

5)	The .ZIP file is retrieved via ftp to another machine.

6)	The .ZIP file is transmitted back to the PC and unZIP'ed back 
into the TELEDISK image file.

7)	The TELEDISK file is processed by TELEDISK to create another copy 
on a different (usually unformatted) diskette.

8)	The descendant floppy is then brought to the DECmate and compared 
against the original floppy proving the process works.

Thus, I wouldn't be too dubious about these files!  It all depends on you 
acquiring the proper PC hardware and utilities and blank DD media.  
(Note: HD media will *not* work!)

cjl