20 Oct
2021
20 Oct
'21
1:31 a.m.
I can't remember now, but I believe the KA was de-supported from Tops-10
in the 6.00 series monitor at some point.
What I recall was that WPI had a version of Tops-10 that was later than
6.03B to where the KA support had been dropped.? They managed to put the
KA back in and this is what we ran.? I /think/ this may have been 6.05.?
WPI also had an odd feature of a 'third' segment, but I couldn't imagine
what that means nor how they did that; I was really starting to focus on
Tops-20 at the time.
I don't remember when SMP showed up, but I'm pretty sure it would have
been in some 600 series monitor.
I had been wondering what the user section count was for the SC30/40.?
The KL can do 5 bits (32 of them), which gets you 8 MW virtual, which is
twice the maximum physical memory.? The TOAD can do 12 bits (4096),
which gets you 1 GW.? I recall that the SC was "in between", but I can't
remember that particular virtual limit.
I had thought that the TOAD (or some version) could do more than 32 KW
physical.
------------------------------------------------------------------------
On 10/19/21 7:07 PM, Peter Lothberg wrote:
Fotnode, MRC gave me the BBN pager from Sails KA, and I later gave it
to LCM, together with? 3 KA's and the BBN pager and the boards for the
KA to connect to the pager. In the late 80's we also did build a
ITS-pager for the KA.
One of the KA's we brought up 6.03A on in 2019. Ralph Gorin pushed the
"read-in" button for that event.
The SC30/SC40 can do "KI-Style" Tops10 10 pager and "KL-Style" Tops
20
paging. The Toad is 'special' it has a lot of the KC10 fetures and
don't do any "KI style" things and has 32MW of memory.
-P
------------------------------------------------------------------------
*From: *"tommytimesharing" <tommytimesharing at gmail.com>
*To: *"hecnet" <hecnet at Update.UU.SE>
*Sent: *Tuesday, October 19, 2021 6:53:31 PM
*Subject: *Re: [HECnet] A2RTR downtime
I understand your point here and you are--of course--correct, yet
one hesitates to term Tops-20 (TWENEX ) paging as being a variant
of the BBN pager (or better TENEX).
The BBN pager was /far/ more capable then the both the KI and KL
pagers.? The KL pager was more capable than the KI, but this
didn't put it quite in the same league as the BBN pager in terms
of functionality.
This is most visible in what RPACS% (Read PAge ACess) returns (or
fails to return) and what SPACS% (Set PAge ACess) does (or fails
to do).? On the KL, the only access bit you can set is whether the
page is writable (this includes Copy-On-Write).? You cannot:
1. Clear all bits and thus set a page 'No Access'; it will still
be there
2. Set a page Write-only
3. Set a page Execute-Only
Case 1. is necessary for implementing guard pages which are (IMHO)
one of the very most effective hardware based debugging tools
around.? You really want "Explode on Reference" to catch stray
reads AND stores.? If you whack the page, then all that happens
the next time you touch it is it 're-materializes'.
Case 2 is great for increasing the security of certain
communications paradigms.
For 1., you can solve it in two convoluted ways. First, you can
hook the page creation interrupt and determine whether you are
creating something you ought not.? You can also actually implement
"Explode on Reference" by mapping 1+ the last page of a locked
file.? If you then try to touch that page, it will fail because
creating the page in memory involves creating it in the (locked)
backing store.? I discovered this by mistake when looking for a
guard page implementation for my FTP server.
2. Has no real solution, but paged mode IPCF% is probably good enough.
3. is partly solved by setting the file execute only, but this is
highly restricted and does not work if a program is multi-process
(I.E., forks).? Thus, I can not use it in the FTP server nor can
it be used in the Tops-20 TELNET client.
BBN repeatedly tried to get DEC to take their pager, but DEC never
went for it.? I don't remember what was designed for the Jupiter
or was implemented for the SC-40 or TOAD.
------------------------------------------------------------------------
On 10/18/21 10:03 PM, Robert Armstrong wrote:
T10 in the last incarnation(s) could use the KL10 paging
Umm.. TOPS-10 could always use the "KL10 paging". TOPS10 ran on
the KL from day 1.
The thing is, the KL had different microcode for TOPS-10 paging and TOPS-20
paging. The hardware didn't change. TOPS-10 paging was the same as the KL10 paging,
which was implemented in hardware. TOPS-20 paging (or rather, TWENEX paging) was some
variant of the BBN pager that was originally attached to a KA10 way back when.
Bob