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IBM 7030 - "Stretch"
Manufacturer IBM Identification,ID IBM 7030 - "Stretch" Date of first manufacture 1961 Number produced 8 - http://www.newmedianews.com/tech_hist/stretch.html Estimated price or cost price ?, less than cost ? location in museum - donor Lawrence Livermore Laboratory, (Gift of Lowell Wood)
Contents of this page:
- Special Features
- Historical Notes
- This Artifact
- Interesting Web Sites
- Other information
- Also see Dr. Dobbs Journal
- IBM 7030 - "Stretch"
- Harwood Kolsky (hardware), Fran Allen (software), Ann Hardy (software), ?, Fred Brooks (software manager) in front of the CHM STRETCH maintenance and operator console after the presentation "IBM Stretch: The Forgotten Computer that Helped Spark a Revolution" at CHM September 11, 2008. Fred Brooks is normally very alert - the long flight and long day must have had effect ;-)) - photo by Robert Garner -
IBM-7030 ("Stretch") - by Ron Mak
Word Length: 64 bits plus 8 bits for parity and error checking. Memory Size: 1 to 8 16K core memory stacks, self-contained wach with its own clock, addressing circuits, data registers and checking circuits, addressing of up to 256k word locations. Data Transfer Rate: Addressing of memories and transfer of information from and to memories ba a memory bus permits new addresses, information, or both to pass through the bus every 0.220 micro-seconds. Central Processor: The processor consists of the instruction unit, the look-ahead unit, a parallel arithmetic unit and a serial arithmetic unit. Multi-programming through program interruption and address monitoring, and over-lapped or parallel execution of instructions is possible. Instruction Format: Half-word formats accommodiate indexing and floating-point instructions. Full-word formats are used by variable-field-length instructions. Five instruction sets and 765 different types of instructions are used. Technology: Standard Modular System Transistor Cards. Used 150,000 high-speed drift transistors, and provided interleaved magnetic core memory with 2.18 usec access cycle.
from Gordon Bell, 10/26/2000, see web site
BTW: the IBM 7090 core was in oil. Not sure about Stretch, but it probably was too as it pioneered technology that the 7090 exploited.
Comments from Bob Bellizzi 10/3/2008
Regarding Gordon Bell's notes on memory The core array was in an aluminum tank, immersed in an oil bath. The oil was circulated through a system that maintened a constant temperature; it had both heating and cooling. The oil allowed the system to maintain the cores at the optimum point for fastest switching which required maximum current and a stable temperature.
The most interesting maintenance issue occurred in the POK mfg building where we put together the first system to ship. We were in the final test phase of manufacturing. Everything was hooked together and the integration was being tested prior to turning it over for acceptance testing. This was not a raised floor so you had to step over masses of cables or end up crushing some of the inter-gate coax.
The memory failed about 10 pm on a Sunday night. Since we were operating a 4 shift, rotation with 6 days on and one day off, we were all punchy. We called Pete Perez back in; he had just left after working 72 hours with less than 12 off per each of the 6 days. He opened the small gates above the core tank. He ran some simple tests and decreed that he had to drain the tank and remove the array (all the joints were soldered). He stuck his head inside the memory rologon frame, removed the appropriate attachments. He bent down, set up a drain system and started to stand up when he hit the latch on the small gate that was swung out. He lost control of the drain and also started bleeding all over the place. The cut wasn't much but blood pours out of the scalp when it gets cut. After he was taken to the hospital we had to clean everything up; took a whole shift to get back on the air. George Werner, who was in charge of the integration team was livid because he had made a schedule that none of us agreed we could meet but still sold it to management. He seemed to think poor Pete did it to give us a break
Comment by Ed Thelen
Ah Yes, the early magnetic core material was quite temperature sensitive. The magnetic characteristics changed quite a bit with temperature, and magnetic flipping used energy and warmed them up. I guess the oil helped stabilize their temperature. I remember magazine articles about the major efforts to find less temperature sensitive core material - which would eliminate the maintenance nightmare of having the core stacks in a tub of oil. Later core stacks (after about 1960) had the cores in air. :-)) A machine I worked on in 1960 (G.E. 225) had core stacks in air, but the core drivers had temperature sensors (thermistors) to adjust their current with the air temperature. Yes, the good old days were "interesting".
from Coslet, Tim July 2004
Comments from Bob Bellizzi 10/3/2008
I've done a bit of research and found that both the 7090 and Stretch did use the same core memory unit:
IBM 7302 - IBM 7030 Core Storage (16384 - 72-bit words: 64 data bits & 8 ECC bits)
IBM 7302 - IBM 7090 Core Storage (32768 - 36-bit words)
It was probably a different model with some different logic (as Stretch used 8 bits of each 72 for ECC and the 7090 used all the bits as data), but it would have been the same core, the same heated oil bath, the same cabinet, etc.
The Tim Coslet section The 7090 core memory was a direct takeoff of the 7030 core memory. The memory bus provided the 7090 with 2 36 bit words at a time instead of one 64 bit plus 8 ECC bits word or 8 bytes and 1 byte ECC so the effective 7090 memory size was 32768 36 bit words.
The interesting thing is that the 7090 could take advantage of what it saw as 2 words fetched at the same time for an effective doubling of memory speed. There was really no interface problem to adapt to the 7090. There was no difference in the memory rologon between 7030 and 7090.
Interesting Web Sites
http://wotug.ukc.ac.uk/parallel/documents/misc/timeline/timeline.txt ========1956======== IBM starts 7030 project (known as STRETCH), with the goal of producing a machine with 100 times the performance of the IBM 704, initiated by Atomic Energy Commission at Los Alamos. (MW,HGK: IBM, STRETCH)========================
from Computer Museum History Center "CORE" 1.2In the early to mid 1950s, IBM and UNIVAC, the only two large companies building computers, were considering the use of transistors in their products. Though the transistor effect had been discovered in 1947 at Bell Labs, vacuum tubes remained commonplace in computer hardware, while American manufacturers struggled to make a reliable, mass-producible transistor. Today it may seem surprising that IBM was undergoing tremendous turmoil about its role in the new field of computers. However, the public had begun to associate the UNIVAC name (not IBM) with computers. CBS's 1952 election coverage included a UNIVAC machine that correctly predicted Eisenhower's victory. And, when former IBM customers started assigning key contracts to UNIVAC, IBM executives took notice. Steve "Red" Dunwell and Werner Buchholz, two senior IBM engineers, proposed a new machine, code-named "Datatron:" Based on transistors, the machine would enable IBM to leap ahead of UNIVAC and would embody many new architectural concepts. 100 TIMES FASTER In a famous memo dated October 25, 1954, Dunwell wrote: "The Datatron program is intended to assure IBM a preeminent position in the field..." and will "take a giant step and make substantial advances on all fronts. " A team of senior IBM technical and management staff met to consider building what John von Neumann had earlier exhorted them to create: "the most advanced machine... possible in the present state of the art." Besides allowing IBM to leapfrog its main competitor, Dunwell argued that the machine would allow IBM to unify its various computer products - roughly divided along scientific and business lines - thus greatly reducing manufacturing costs and simplifying IBM's engineering and production processes. After great internal debate and a contract from Los Alamos Scientific Laboratory, the project went ahead. Now codenamed "Stretch," the machine was to be "100 times faster than the most advanced computer working today," and President Tom Watson proudly noted that the new machine could complete "100 billion computations in a day." THE NEWS SPREADS The first machine (officially named the IBM 7030) was delivered to Los Alamos on April 16, 1961. Although far short of being 100 times faster than competing machines, it was accepted and ran for the next 10 years, with the thenastonishing average reliability of 17 hours before failure. While customers were generally happy with the machine's performance, internally, Stretch was considered a failure for not meeting its speed benchmark. IBM reduced the price from $13.5 million to $7.78 million, thus guaranteeing that every machine was built at a loss. Dunwell's star within IBM fell dramatically, and he was given fewer responsibilities. As time went on, however, attitudes within IBM changed. From a lagging position in industry, IBM had moved into the forefront through the manufacturing, packaging, and architectural innovations Stretch had fostered. Dunwell's exile ended in 1966, when the contributions Stretch had made to the development of other IBM machines including the monumentally successful System/360 product line - became evident. Dunwell was made an IBM Fellow that year, the company's highest honor. THE SUCCESSFUL FAILURE The Stretch story is only one of many in the history of computing that shows how triumphs are built upon the ashes of "failures:" Stretch is one of the hallmark machines - despite its near invisibility to history - that defined the limits of the possible for later generations of computer designers and users. You may recognize many Stretch innovations in present-day products: Multiprogramming Memory protection Generalized interrupt system Pipelining Memory interleaving Speculative execution Lookahead (overlap of memory and arithmetic ops) Concept of a memory bus Coupling two computers to a single memory Large core memory ( 1MB) The eight-bit character (the "byte") Variable word length Standard I/0 interface Ironically, microprocessor companies 20 or 30 years later "re-invented" most of these innovations. The Computer Museum History Center has parts of the original Stretch machine (serial number 1) from Los Alamos and a complete. Stretch (minus core memory unit) from the Lawrence Livermore National Laboratory. STRETCH SPECS The Stretch covered 2,500 square feet, the size of the average American home, and weighed approximately 40,000 Ibs. The CPU alone was 900 square feet (30' x 6' x 5'). Nine machines were ultimately produced and sold for $7.78 million each (1961 dollars). The processing units alone used 21kW. Stretch employed aggressive uniprocessor parallelism; had an instruction set of 735 instructions (including modes) of variable field length; used magnetic core memory (6 x 16KW, 2.1us cycle time): and had 169,200 transistors. The basic machine cycle was 300ns (3.3 MHz), and it performed at approximately 500 KIPS (code dependent). Stretch accommodated word lengths of 64 + 8 check bits (SECDED), had a disk of 2MW and 8Mbps, and used magnetic tape in its 12 x IBM 729 IV tape drives. The machine had a 1,000 cpm (card per minute) card reader; a 600 Lpm printer; and a 250 cpm card punch. FURTHER READING Bashe, Charles, et al. IBM's Early Computers. Cambridge: MIT Press, 1986, pp. 416-468. Blaauw, Gerritt, & Brooks, Frederick. Computer Architecture: Concepts and Evolution. New York: Addison Wesley, 1997. Buchholz, Werner. Planning a Computer System: Project Stretch. New York: McGraw-Hill Book Company, 1962. Out of print. Dunwell, S. W. "Design Objectives for the IBM Stretch Computer." Proc. Eastern Joint Computer Conference. December 1956, pp. 20-22. - - - - - - - - - - - - - - Dag Spicer is Curator & Manager of Historical Collections - at The Computer Museum History Center A version of this article first appeared in Dr. Dobbs Journal online.
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Updated September 11, 2008