On Sat, 9 Dec 2017 15:55:40 +0000 (UTC), Kiwi User
 declaimed the following:

>On Fri, 08 Dec 2017 21:45:34 -0500, Dennis Lee Bieber wrote:
>
>
>I'd believe that minis were somewhat different from mainframes. After all

 Just an FYI: The Sigma was a mainframe -- using four refrigerator sized
boxes for the 4-port/4-bank, interleaved, core, one such box for CPU, and a
few others for the various I/O Processors (serial/sequential IOP for tape
drives I think, and Multiplexed IOP for terminal server, disk drives,
printers/card readers) -- meant to compete with the IBM 360. I don't recall
the actual sizes of the drives used by the college (mere students don't
need to know such) but as I recall, a high point came when they obtained
two new drives dedicated to swap space (considering we supported some 50+
terminals/users in a machine with around 512kB of core) -- swap drives were
whopping 300MB as I recall.

>they were a generation later. I did some preliminary design and coding
>for a PDP8 job before being yanked off it and sent to NYC in a project
>involving an ICL 2903 [1]. But, IIRC the PDP-8 used 8.3 format filenames
>in a single directory per disk and had no concept of file ownership - IOW
>CM/M, DRDOS, FLEX and MSDOS (before it got directories) filing systems
>were virtually direct copies of the venerable PDP-8 filing system.
>

 Sigma filenames were, as I recall, 32-characters (not counting
file-password/owner-account -- which is a misnomer as logging in required
user-ID, billing account, and password); filename could include some
punctuation (including ! great way to obscure a file name since the
audio delay when listing the directory didn't reveal where in the name the
 was hidden). Files were "owned" as their space was accounted for in
the user's quota (deleting a large file using the cross-account access
could temporarily result in a quota increase for the account that did the
deletion). Obviously no protection levels other than the optional password
field.

 Unlike TRS-DOS 3 (and carried into LS-DOS 5). A full filespec was
filename/ext.passwod:# (8.3.8 and # being logical drive # 0-7). Files had
two passwords: master (needed to invoke the attrib command on the file) and
user. The user password only had access as specified in the attrib command
-- so one could set a program file to be execute-only and STILL require a
password to run it. LS-DOS/TRSDOS 6 lost the user password when a change
was made to allow for more than a 7-year date range (you thought Y2K was
bad, TRSDOS 6 was something like 1980-1987 ). Most people never set a
user password anyway. Supplying drive numbers wasn't done much either on
most (dual floppy) systems -- one would write protect the system disk,
leaving the other drive for data. The OS would scan mounted disks for
existing filenames, and would create new files on the first write-enabled
drive.


--
 Wulfraed                 Dennis Lee Bieber         AF6VN
    wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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