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Launch of project
"Charlie"
As a conservative measure to keep some
engineers on board, BULL-General Electric, with GE agreement,
assigned to Pierre DAVOUS, assisted by Georges LEPICARD, an
exploratory mission to specify a line of medium sized machines that
could be sold competitively with IBM 360 –the IBM product line
then emerging as a definitive success–.
That line of products would have to be micro-programmed, a technique
that the Bull team was the only one having experimented inside GE
with the projects M40 and GE140.
This project received the name of "Project CHARLIE".
A few Americans from Phoenix
engineering, noticeably Izzy EPSTEIN, joined a research team of
around 20 French people.
Some of the basic design options of the DPS7
have been taken during this study. Particularly, it was decided to
have an architecture now known as CISC using 32 bits registers à la
S/360 and to introduce some MULTICS segmentation features. It
was also considered that real-time transactional applications should
merit a firmware implementation of the process (presently
named threads) dispatching mechanism. A first draft of the
instruction code set was established. Several models were
contemplated differing by the width of their data path (16 and 32
bits).
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During this period, GE hired an ex-IBMer,
John HAANSTRA, as vice-president for Strategy. He took
a direct interest in the design options of the CHARLIE
project. |
John Haanstra
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John HAANSTRA recommended that the
peripheral controllers (PCP Peripheral Control Processors) be
micro-programmed, avoiding special logic as much as possible, and
the Bull URC -- that was later followed by its cousins like
the Phoenix MPC and the NEC URP, was initiated by Henri VERDIER team
on the base of J.HAANSTRA recommendations.
In parallel, technology studies were initiated: while the choice of
integrated circuits was obvious (RCA had already shipped its
Spectra70 line), several solutions were possible for the transistors
types. GE had started in Schenectady the study of CML – a
variant of ECL, slightly less power-hungry– and CML was a
potential candidate for the new line of systems in parallel with TTL.
General Electric L178 Product Line
Outline
A GE Management review took place at the end
of 1967 and it was decided that the Bull Charlie study should
be the base of a modern GE product line essentially targeted to
replace GE-100 and GE-400 product lines.
This product line should have been designed
jointly by GEISI, Bull and the GE400 team of Phoenix. The GE600 team
of Phoenix was then busy to fix design and implementation problems
in both the GECOS3 and the MULTICS systems and was let apart of the
new design. ASTO research center in Phoenix, directed by John WEIL
and Mauro PACELLI, was to be deeply involved in the project.
It was decided to review the options of the
Bull study (project Charlie) and to launch a project called L178
product line composed of three models:
- E120 as a 16-bit low-end machine
assigned to GEISI,
- R370 to be developed by Bull
General Electric
- W108 a more powerful system to be
developed by GE Phoenix.
A strict security system, à la IBM, was
instituted for the new design. Code names were formed from the
initials of the project manager and documents were classified as GE
class4 for all business planning and financially sensitive matters
and class3 for technical matters. Class4 documents received a number
for each page and they were distributed according a centralized and
nominative list of distribution. Class3 documents were distributed
according "need to know" lists of distribution. It seems
that no leak to the press or to the outside occurred during that
phase of the design .
The project started effectively
in January 1968 under the effective direction of Eugen R. WHITE
as a project manager reporting directly to John.HAANSTRA.
A coordination team was
assembled in Phoenix ;
the chief architect was Georges LEPICARD from Bull-GE,
the software project leader was Leroy ELLISON from GE |
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Some Bull hardware architects from BULL --G.BARONNAT
and G.de PONCINS, joined the Phoenix team for around a year.
Specific program managers were assigned in
the different organizations to coordinate local work and to report
to the overall program manager. Jean-Pierre HARDY was program
manager for the R370 to be developed by Paris.
The architecture was coordinated by George
LEPICARD and discussed between the CPU architects, the compiler
designers of ASTO and the Paris software people for the kernel (then
called nucleus) requirements. The first draft of the "Interior
decor" –this term was coined at this time by ASTO
software people– was published by September 1968.
E120 Compatibility. Origin of Level 62
divergence
The E120 architecture was accepted as
being a "subset" of the main line "interior
decor". Consequently, a large autonomy was given to the
designers of what became eventually the Level 62 about the
design of their architecture and their software. The divergence
between DPS4 and DPS7 took place in 1968! However, at that time, it
was implied that the upper range of the line should be able to
operate in the lower level "mode"; this specification was
later dropped.
It was initially envisioned that the E120
decor had to be the same as the one of the PCP, so that a single
engine could be used on the subsystems and on the lower end of the
line. This last approach was abandoned by November 1968, at Paris
request to use a minicomputer 16-bit decor instead of a variable
length "main frame" decor for the PCP.
The E120 project subsisted through the
GE-Honeywell merger and gave birth to the Series 60 Level 62 product
line.
Software
A proprietary high level Implementation
language for software development was planned : Q-language,
an ALGOL60 derived language, was designed, but actually never
implemented.
The assignments of Software tasks to the
development teams of Bull and Medium System Department in Phoenix
were made: Bull abandoned for some years any work on COBOL, while
some competence in basic operating system was attributed to what was
then a very inexperienced Bull team.
An ACT team, under the
responsibility of MIKE BAILEY reviewed the results of the
preliminary software studies. That report was essentially
confirming the initial design decisions about the use of segmentation,
condemning demand paging in the sake of performances, recommending
however paging as a tool for memory chunks allocation. It was
insisting on the use of a powerful Macro- generator, both as
a software methodology tool and as a job control language extension.
It also let Management unwary about the "subsettability"
of the interior decor, assuming that segmentation mechanism could be
specific to a hardware model, without impacting the software unicity.
It might have been that ACT was hunting from contracts in several GE
divisions!
Architecture approaches
That period was marked by a cross-culture
exchange in the software area between the GE600 world, the S/360
influence on Bull designers and the Burroughs culture that
predominated in ASTO.The name of ASTO's Jack MERNER, one of the key
architects of the Burroughs B5000, and that of Mauro PACELLI, head
of sofware ASTO unit should be mentioned.
The Bull initial interior decor was
then complemented by the implementation of a stack mechanism
handled by firmware for parameters passing, while the arithmetics
remain in S/360-like registers.
The general conventions of a static linkage
mechanism were established. The introduction of the "process"
concept in the interior decor was confirmed, although many designers
from GECOS3 and MULTICS were very reluctant to freeze the software
design of those architecture elements. [Note that L178 Processes
are called threads in recent Operating systems terminology.]
The concept of Process group and its
identification as job steps' occurrences were introduced during that
period.
A "Smart indexing", i.e., indexing
modulo a length dependent upon the operand type was introduced.
Retrospectively, it appears that too much
importance was given to the ease of implementation of some
languages' features by compilers at the expense of CPU performances
for high-end machines. It was assumed that all the machines would be
micro-programmed (in PROM), a difference with the S/360 decor where
the assumption was that the majority of instructions. should be
wired-on in the upper end processor.
A use of ASCII code was planned
at that time because IBM was then to have an ASCII mode on S/360 and
because the overall culture of GE Computer Division was extremely
reluctant to target any kind of IBM compatibility, such as the
EBCDIC encoding , that was selected later.
Technology
Two Technologies were considered : a SUHL
Sylvania technology as used in the GE600 and a CML (Current Mode
Logic) technology developed in GE laboratories. Eventually, the CML
was chosen as the base of the study, probably due to an intense
lobbying of research people in front of John Haanstra, a
manager who remained technically minded.
Although the level of integration of CML was
at that time extremely embryonic, that technology was chosen for its
performances and its (relatively) low power consumption.
The main memory was assumed initially to be magnetic
core in spite of its labor intensive cost figures ; at that
time, GE was planning to set up a core weaving factory ...in the
Navajo reservation! You should note that the intended manufacturing
cost of a 32-bits CPU later was planned to be 8,900 1970-dollars,
while memory's cost was expected to be 8,000 dollars per 32K Bytes!
The R370 CPU was to be developed in Paris -
under the direction of Jacques BIENVENU ; it had to be based on
hardware blocks, planned to be common to all the components of
L-178, called SOMA (System Oriented Macro Assembly). Those SOMA were
envisioned to be eventually LSIfied in a future version
I/O Subsystems
The peripheral controllers of the main line
were to be developed on a common design of the Bull URC, while E120
peripherals had to be "integrated" and controlled by the
CPU firmware..
The overall architecture of the PSI
Channel --Peripheral Subsystem Interface, was
drafted at that time.
Because the 8-bit byte orientation of the
L-178, the PSI had to be a parallel 8-bit channel. For data
integrity reasons, due to the relatively low reliability of the
subsystems of that time, it was excluded that PCPs had a direct
access (DMA) to the main memory and decided that those accesses had
to be controlled by the CPU itself.
A separate IOC (input-output controller),
regrouping the channels' access to the system memory, was not
envisioned at that time for cost reasons. It was also considered
that the PSI should be the "long" cables in the system
because the interface between the PCP and the devices might have to
be specific and ought to control a "real-time" interface.
This general design was later adopted for both the new product line
and the GE-600+ line. In the latter, PSI channels -- although never
actually identical to the NPL ones, supersede progressively the old
(1965) Common Peripheral Interface (CPI) 6-bits wide channels.
It may be interesting to note that the main
Discs that were contemplated at that time were removable discs with
a 17MBytes(!) capacity and a transfer rate of 468KB/s. Future (1975)
discs with up to 300MBytes were envisioned.
The L-178 systems remained punched card
oriented. GE was assuming a development of optical- reading of
documents that was never materialized. Impact printers had, at that
time, already reached their maturity (at 1300lpm).
Reliability
The expected reliability was poor in face of
present standards, no more than a MTBF of 100 hours. That was due to
the low level of integration of the technology and consequently to
the amount of connectors and cards existing in the system. It was
expected to spend a large amount of hardware to check the system
data integrity and to insert control probes.
End of L-178
At the end of 1968, the results were not
satisfactory in the technology and hardware design areas: the
building blocks (SOMA) were too numerous and the CML was not ready
to be used by the 1970 time frame.
John HAANSTRA was asked to take direct
responsibility of Phoenix engineering to reorganize the GE655
--alias GE6000, project and Gene WHITE left the company.
Bull reconsidered the R530 project in a more
conventional TTL technology as a System730 and the Italian
acted similarly.
Phoenix MSD -Medium Systems Department- was
disbanded and merged with LISD (the GE600 engineering group). |
