Scope Timesharing

[Jerry Brod]

I read in "A Few Good Men From Univac" that the MACE operating system
was chosen as the base for writing a timesharing operating system
(KRONOS) for the 6000 series machines because the current version of
SCOPE was too slow at switching between jobs. Does anyone have a more
detailed explanation of what was the difficulty in adding timesharing
to SCOPE?

[Jitze Couperus]

Post by Jerry Brod
I read in "A Few Good Men From Univac" that the MACE operating system
was chosen as the base for writing a timesharing operating system
(KRONOS) for the 6000 series machines because the current version of
SCOPE was too slow at switching between jobs. Does anyone have a more
detailed explanation of what was the difficulty in adding timesharing
to SCOPE?

I don't think there was a difficulty - in that timesharing adjuncts
were developed under SCOPE (TTY-Respond, SOS, and later Intercom)
very early (before I became aware of KRONOS - although it may have
been in the works at the same time)

My take is that the alleged "difficulty" was more of a not-
invented-here phenomenon which regularly plagued
relations between the tie-wearing upright Minnesota contingent
and those wacky Californians.

Jitze

[Don Foret]

Jerry,

I have experience with both SCOPE and KRONOS dating back to 1969. My initial
experience was with SCOPE at the FSU Computing Center. I was a student at
the time and worked in the Computer Center part time. I remember our
difficulties with SCOPE and performance and much of it had to do with the
limited number of control points and memory management.

With SCOPE you had a limited number of control points (7 at the time I was
using it) which were required to execute a time sharing time slot. Each time
a time-sharing user needed attention it needed to be rolled in and executed.
Usually the time required to roll-in and roll-out a job far exceeded the
actual CPU time required. With such a small number of Control Points
available this was usually a bottle-neck. Another issue was memory. SCOPE
assumed the central memory was locked and immovable unless the PPU allowed
memory movement to take place. Remember each control point contained an
exchange package that contained the beginning address of the program in
memory and its length. So, SCOPE had to wait until a PPU allowed memory
movement.

KRONOS, on the other hand, assumed that memory could be moved unless locked
by a MTR call. This basic difference along with the larger number of control
points in KRONOS (up to 40--if I recall correctly) made control points
readily available for timesharing sessions. The fact that memory was not
locked unless specifically requested made rolling out lower priority batch
jobs much faster than under SCOPE. KRONOS also used the CPU to move memory
which was much faster than SCOPE's PPU memory movement scheme.

After FSU switched to KRONOS we were able to support up to 10 times more
timesharing sessions than we could under SCOPE.

I later went to work for CDC in the KRONOS development group in Arden Hills
and worked there until the summer of 1976.

I hope this helps.

[Rich Ragan]

I didn't know you were at the FSU Computing Center, Don. You were a bit
after my time since I graduated in 1967 and was at Purdue until 1969
then on to Palo Alto to the compiler group. I have been in touch with
Mike Mann and John Nall from time to time. There has been talk of an old
FSU computer center alums get together but I think it got back burnered.

Cheers, Richard Ragan

Post by Don Foret
Jerry,
I have experience with both SCOPE and KRONOS dating back to 1969. My initial
experience was with SCOPE at the FSU Computing Center. I was a student at
the time and worked in the Computer Center part time. I remember our
difficulties with SCOPE and performance and much of it had to do with the
limited number of control points and memory management.

[Don Foret]

Richard,

Did you know Bruce McLennan. He graduated from FSU and went to Purdue. I
think he got his PhD and then went to work for Intel. I worked for John but
I don't remember Mike Mann. I spent a lot of time in Sunnyvale in 1975 when
the NOS work was getting done at SVLOPS. Did you know Bob Tate or Lee Hammer
from the Kronos development group.?
--
Don Foret

Post by Rich Ragan
I didn't know you were at the FSU Computing Center, Don. You were a bit
after my time since I graduated in 1967 and was at Purdue until 1969
then on to Palo Alto to the compiler group. I have been in touch with
Mike Mann and John Nall from time to time. There has been talk of an old
FSU computer center alums get together but I think it got back burnered.
Cheers, Richard Ragan

Post by Don Foret
Jerry,
I have experience with both SCOPE and KRONOS dating back to 1969. My initial
experience was with SCOPE at the FSU Computing Center. I was a student at
the time and worked in the Computer Center part time. I remember our
difficulties with SCOPE and performance and much of it had to do with the
limited number of control points and memory management.

[Rich Ragan]

Can't say I remember Bruce McLennan. I expect I just missed him at
Purdue much as we did not cross paths at FSU. I certainly knew Lee
Hammer and even now sometimes exchange an email with Bob Tate.
The name Paul Spivey is familiar but I think he came after my time.

Post by Don Foret
Richard,
Did you know Bruce McLennan. He graduated from FSU and went to Purdue. I
think he got his PhD and then went to work for Intel. I worked for John but
I don't remember Mike Mann. I spent a lot of time in Sunnyvale in 1975 when
the NOS work was getting done at SVLOPS. Did you know Bob Tate or Lee Hammer
from the Kronos development group.?

[ADF]

Do you have Bob's email address? I've really like to contact him.

Post by Rich Ragan
Can't say I remember Bruce McLennan. I expect I just missed him at
Purdue much as we did not cross paths at FSU. I certainly knew Lee
Hammer and even now sometimes exchange an email with Bob Tate.
The name Paul Spivey is familiar but I think he came after my time.

Post by Don Foret
Richard,
Did you know Bruce McLennan. He graduated from FSU and went to Purdue. I
think he got his PhD and then went to work for Intel. I worked for John but
I don't remember Mike Mann. I spent a lot of time in Sunnyvale in 1975 when
the NOS work was getting done at SVLOPS. Did you know Bob Tate or Lee Hammer
from the Kronos development group.?

[Don Foret]

Rich,

Also, did you know Paul Spivey? He was the resident CDC S/W Analyst on site?
I know he had been there for a couple of years before I arrived. Last I
heard he was living somewhere in Oklahoma.
--
Don Foret

Post by Rich Ragan
I didn't know you were at the FSU Computing Center, Don. You were a bit
after my time since I graduated in 1967 and was at Purdue until 1969
then on to Palo Alto to the compiler group. I have been in touch with
Mike Mann and John Nall from time to time. There has been talk of an old
FSU computer center alums get together but I think it got back burnered.
Cheers, Richard Ragan

Post by Don Foret
Jerry,
I have experience with both SCOPE and KRONOS dating back to 1969. My initial
experience was with SCOPE at the FSU Computing Center. I was a student at
the time and worked in the Computer Center part time. I remember our
difficulties with SCOPE and performance and much of it had to do with the
limited number of control points and memory management.