CDC 6600
Encyclopedia
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...
from Control Data Corporation
Control Data Corporation
Control Data Corporation was a supercomputer firm. For most of the 1960s, it built the fastest computers in the world by far, only losing that crown in the 1970s after Seymour Cray left the company to found Cray Research, Inc....
, first delivered in 1964. It is generally considered to be the first successful supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...
, outperforming its fastest predecessor, IBM 7030 Stretch, by about three times. With performance of about 1 megaFLOPS
FLOPS
In computing, FLOPS is a measure of a computer's performance, especially in fields of scientific calculations that make heavy use of floating-point calculations, similar to the older, simpler, instructions per second...
, it remained the world's fastest computer from 1964–69, when it relinquished that status to its successor, the CDC 7600
CDC 7600
The CDC 7600 was the Seymour Cray-designed successor to the CDC 6600, extending Control Data's dominance of the supercomputer field into the 1970s. The 7600 ran at 36.4 MHz and had a 65 Kword primary memory using core and variable-size secondary memory...
.
The system organization of the CDC 6600 was used for the simpler (and slower) CDC 6400
CDC 6400
The CDC 6400, a member of the CDC 6000 series, was a mainframe computer made by Control Data Corporation in the 1960s. The central processing unit was architecturally compatible with the CDC 6600...
, and later a version containing two 6400 processors known as the CDC 6500. These machines were instruction-compatible with the 6600, but ran slower due to a much simpler and more sequential processor design. The entire family is now referred to as the CDC 6000 series
CDC 6000 series
The CDC 6000 series was a family of mainframe computers manufactured by Control Data Corporation in the 1960s. It consisted of CDC 6400, CDC 6500, CDC 6600 and CDC 6700 computers, which all were extremely rapid and efficient for their time...
. The CDC 7600
CDC 7600
The CDC 7600 was the Seymour Cray-designed successor to the CDC 6600, extending Control Data's dominance of the supercomputer field into the 1970s. The 7600 ran at 36.4 MHz and had a 65 Kword primary memory using core and variable-size secondary memory...
was originally to be compatible as well, starting its life as the CDC 6800, but during the design compatibility was dropped in favor of outright performance. While the 7600 CPU remained compatible with the 6600, allowing portable user code, the peripheral processor units (PPUs) were different, requiring a different operating system.
A CDC 6600 is on display at the Computer History Museum
Computer History Museum
The Computer History Museum is a museum established in 1996 in Mountain View, California, USA. The Museum is dedicated to preserving and presenting the stories and artifacts of the information age, and exploring the computing revolution and its impact on our lives.-History:The museum's origins...
in Mountain View, California
Mountain View, California
-Downtown:Mountain View has a pedestrian-friendly downtown centered on Castro Street. The downtown area consists of the seven blocks of Castro Street from the Downtown Mountain View Station transit center in the north to the intersection with El Camino Real in the south...
.
History and impact
CDC's first products were based on the machines designed at ERAEngineering Research Associates
Engineering Research Associates, commonly known as ERA, was a pioneering computer firm from the 1950s. They became famous for their numerical computers, but as the market expanded they became better known for their drum memory systems. They were eventually purchased by Remington Rand and merged...
, which Seymour Cray
Seymour Cray
Seymour Roger Cray was an American electrical engineer and supercomputer architect who designed a series of computers that were the fastest in the world for decades, and founded Cray Research which would build many of these machines. Called "the father of supercomputing," Cray has been credited...
had been asked to update after moving to CDC. After an experimental machine known as the Little Character, they delivered the CDC 1604
CDC 1604
The CDC 1604 was a 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation. The 1604 is known as the first commercially successful transistorized computer. Legend has it that the 1604 designation was chosen by adding CDC's first street address to...
, one of the first commercial transistor-based computers
Transistor computer
A transistor computer is a computer which uses discrete transistors instead of vacuum tubes. The "first generation" of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky, and were unreliable. A "second generation" of computers, through the late 1950s and...
, and one of the fastest machines on the market. Management was delighted, and made plans for a new series of machines that were more tailored to business use; they would include instructions for character handling and record keeping for instance. Cray was not interested in such a project, and set himself the goal of producing a new machine that would be 50 times faster than the 1604. When asked to complete a detailed report on plans at one and five years into the future, he wrote back that his five year goal was "to produce the largest computer in the world", "largest" at that time being synonymous with "fastest", and that his one year plan was "to be one-fifth of the way".
Taking his core team to new offices nearby the original CDC headquarters, they started to experiment with higher quality versions of the "cheap" transistor
Transistor
A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...
s Cray had used in the 1604. After much experimentation, they found that there was simply no way the germanium
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....
-based transistors could be run much faster than those used in the 1604. The "business machine" that management had originally wanted, now forming as the CDC 3000
CDC 3000
The CDC 3000 series computers from Control Data Corporation were mid-1960s follow-ons to the CDC 1604 and CDC 924 systems. Over time, a range of machines were produced - divided into the 'upper 3000 series' and the 'lower 3000 series'. CDC phased out production of the 3000 series in the early 1970s...
series, pushed them about as far as they could go. Cray then decided the solution was to work with the then-new silicon
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
-based transistors from Fairchild Semiconductor
Fairchild Semiconductor
Fairchild Semiconductor International, Inc. is an American semiconductor company based in San Jose, California. Founded in 1957, it was a pioneer in transistor and integrated circuit manufacturing...
, which were just coming onto the market and offered dramatically improved switching performance.
During this period, CDC grew from a startup to a large company and Cray became increasingly frustrated with what he saw as ridiculous management requirements. Things became considerably more tense in 1962 when the new CDC 3600 started to near production quality, and appeared to be exactly what management wanted, when they wanted it. Cray eventually told CDC's CEO, William Norris
William Norris
William Charles Norris was the pioneering CEO of Control Data Corporation, at one time one of the most powerful and respected computer companies in the world...
that something had to change, or he would leave the company. Norris felt he was too important to lose, and gave Cray the green light to set up a new lab wherever he wanted.
After a short search, Cray decided to return to his home town of Chippewa Falls, WI, where he purchased a block of land and started up a new lab. Although this process introduced a fairly lengthy delay in the design of his new machine, once in the new lab things started to progress quickly. By this time, the new transistors were becoming quite reliable, and modules built with them tended to work properly on the first try. Working with Jim Thornton, who was the system architect and the 'hidden genius' behind the 6600, the machine soon took form.
More than 100 CDC 6600s were sold over the machine's lifetime. Many of these went to various nuclear bomb-related labs, and quite a few found their way into university computing labs. Cray immediately turned his attention to its replacement, this time setting a goal of 10 times the performance of the 6600, delivered as the CDC 7600
CDC 7600
The CDC 7600 was the Seymour Cray-designed successor to the CDC 6600, extending Control Data's dominance of the supercomputer field into the 1970s. The 7600 ran at 36.4 MHz and had a 65 Kword primary memory using core and variable-size secondary memory...
. The later CDC Cyber
CDC Cyber
The CDC Cyber range of mainframe-class supercomputers were the primary products of Control Data Corporation during the 1970s and 1980s. In their day, they were the computer architecture of choice for scientific and mathematically intensive computing...
70 and 170 computers were very similar to the CDC 6600 in overall design.
Description
Typical machines of the era used a single complex CPUCentral processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
to drive the entire system. A typical program would first load data into memory (often using pre-rolled library code), process it, and then write it back out. This required the CPUs to be fairly complex in order to handle the complete set of instructions they would be called on to perform. A complex CPU implied a large CPU, introducing signalling delays while information flowed between the individual modules making it up. These delays set a maximum upper limit on performance, the machine could only operate at a cycle speed that allowed the signals time to arrive at the next module.
Cray took another approach. At the time, CPUs generally ran slower than the main memory they were attached to. For instance, a processor might take 15 cycles to multiply two numbers, while each memory access took only one or two. This meant there was a significant time where the main memory was idle. It was this idle time that the 6600 exploited.
Instead of trying to make the CPU handle all the tasks, the 6600s handled arithmetic and logic only. This resulted in a much smaller CPU which could operate at a higher clock speed. Combined with the faster switching speeds of the silicon transistors, the new CPU design easily outperformed everything then available. The new design ran at 10 MHz (100 ns cycle), about ten times faster than other machines on the market. In addition to the clock being faster, the simple processor executed instructions in fewer clock cycles; for instance, the CPU could complete a multiplication in ten cycles.
However, the CPU could only execute a limited number of simple instructions. A typical CPU of the era had a complex instruction set
Complex instruction set computer
A complex instruction set computer , is a computer where single instructions can execute several low-level operations and/or are capable of multi-step operations or addressing modes within single instructions...
, which included instructions to handle all the normal "housekeeping" tasks such as memory access and input/output
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
. Cray instead implemented these instructions in separate, simpler processors dedicated solely to these tasks, leaving the CPU with a much smaller instruction set. (This was the first of what later came to be called reduced instruction set computer
Reduced instruction set computer
Reduced instruction set computing, or RISC , is a CPU design strategy based on the insight that simplified instructions can provide higher performance if this simplicity enables much faster execution of each instruction. A computer based on this strategy is a reduced instruction set computer...
(RISC) design.) By allowing the CPU, peripheral processors (PPs) and I/O to operate in parallel, the design considerably improved the performance of the machine. Under normal conditions a machine with several processors would also cost a great deal more. Key to the 6600's design was to make the I/O processors, known as peripheral processors (PPs), as simple as possible. The PPs were based on the simple 12-bit CDC 160A
CDC 160A
The CDC 160 and CDC 160-A were 12-bit minicomputers built by Control Data Corporation from 1960 to 1965. The 160 was designed by Seymour Cray - reportedly over a long three-day weekend...
, which ran much slower than the CPU, gathering up data and "squirting" it into main memory at high speed via dedicated hardware.
The machine as a whole operated in a fashion known as barrel and slot, the "barrel" referring to the ten PPs, and the "slot" the main CPU. For any given slice of time, one PP was given control of the CPU, asking it to complete some task (if required). Control was then handed off to the next PP in the barrel. Programs were written, with some difficulty, to take advantage of the exact timing of the machine to avoid any "dead time" on the CPU. With the CPU running much faster than on other computers, each memory access took ten CPU clock cycles to complete, so by using ten PPs, each PP was guaranteed one memory access per machine cycle.
The 10 PPs were implemented virtually; there was CPU hardware only for a single PP. This CPU hardware was shared and operated on 10 PP register sets which represented each of the 10 PP states (similar to modern multithreading
Temporal multithreading
Temporal multithreading is one of the two main forms of multithreading that can be implemented on computer processor hardware, the other being simultaneous multithreading. The distinguishing difference between the two forms is the maximum number of concurrent threads that can execute in any given...
processors). The PP register barrel
Barrel processor
A barrel processor is a CPU that switches between threads of execution on every cycle. This CPU design technique is also known as "interleaved" or "fine-grained" temporal multithreading...
would "rotate", with each PP register set presented to the "slot" which the actual PP CPU occupied. The shared CPU would execute all or some portion of a PP's instruction whereupon the barrel would "rotate" again, presenting the next PP's register set (state). Multiple "rotations" of the barrel were needed to complete an instruction. A complete barrel "rotation" occurred in 1000 nanoseconds (100 nanoseconds per PP), and an instruction could take from 1 to 5 "rotations" of the barrel to be completed, or more if it was a data transfer instruction.
The basis for the 6600 CPU is what would today be referred to as a RISC system, one in which the processor is tuned to do instructions which are comparatively simple and have limited and well-defined access to memory. The philosophy of many other machines was toward using instructions which were complicated — for example, a single instruction which would fetch an operand from memory and add it to a value in a register. In the 6600, loading the value from memory would require one instruction, and adding it would require a second. While slower in theory due to the additional memory accesses, the PPs offloaded this expense. This simplification also forced programmers to be very aware of their memory accesses, and therefore code deliberately to reduce them as much as possible.
Central Processor (CP)
The Central Processor (CP) and main memory of the 6400, 6500, and 6600 machines had a 60-bit word length. The Central Processor had eight general purpose 60-bit60-bit
Computers with 60-bit words include the CDC 6000 series and some of the CDC Cyber series....
registers
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
X0 through X7, eight 18-bit
18-bit
18 binary digits have unique combinations.-Example 18-bit computer architectures:* Possibly the most well-known 18-bit computer architectures are the PDP-1, PDP-4, PDP-7, PDP-9 and PDP-15 minicomputers produced by Digital Equipment Corporation from 1960 to 1975.* UNIVAC produced a number of...
address registers A0 through A7, and eight 18-bit scratchpad registers B0 through B7. B0 was held permanently at zero by the hardware; many programmers found it useful to set B1 to 1 and then treat it as similarly inviolate.
The CP had no instructions for input and output, which are accomplished through Peripheral Processors (below). No opcodes were specifically dedicated to loading or storing memory; this occurred as a side effect of assignment to certain A registers. Setting A1 through A5 loaded the word at that address into X1 through X5 respectively; setting A6 or A7 stored a word from X6 or X7. No side effects were associated with A0.
A separate hardware load/store unit handled the actual data movement independently of the operation of the instruction stream, allowing other operations to complete while memory was being accessed, which required (best case) eight cycles.
The 6600 CP included 10 parallel functional units, allowing multiple instructions to be worked on at the same time. Today, this is known as a superscalar
Superscalar
A superscalar CPU architecture implements a form of parallelism called instruction level parallelism within a single processor. It therefore allows faster CPU throughput than would otherwise be possible at a given clock rate...
design, but it was unique for its time. Unlike most modern CPU designs, functional units were not pipelined; the functional unit would become busy when an instruction was "issued" to it and would remain busy for the entire time required to execute that instruction. (By contrast, the CDC 7600 introduced pipelining into its functional units.) In the best case, an instruction could be issued to a functional unit every 100 ns clock cycle. The system read and decoded instructions from memory as fast as possible, generally faster than they could be completed, and fed them off to the units for processing. The units were:
- floating point multiply (2 copies)
- floating point divide
- floating point add
- "long" integer add
- incrementers (2 copies; performed memory load/store)
- shift
- boolean logic
- branch
Floating-point operations were given pride of place in this architecture
Computer architecture
In computer science and engineering, computer architecture is the practical art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals and the formal modelling of those systems....
: the CDC 6600 (and kin) stand virtually alone in being able to execute a 60-bit floating point
Floating point
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
multiplication in time comparable to that for a program branch.
Previously executed instructions were saved in an eight-word cache
Cache
In computer engineering, a cache is a component that transparently stores data so that future requests for that data can be served faster. The data that is stored within a cache might be values that have been computed earlier or duplicates of original values that are stored elsewhere...
, called the "stack". In-stack jumps were quicker than out-of-stack jumps because no memory fetch was required. The stack was flushed by an unconditional jump instruction, so unconditional jumps at the ends of loops were conventionally written as conditional jumps that would always succeed.
The system used a 10-megahertz clock, but used a four-phase signal, so the system could at times effectively operate at 40 MHz. A floating-point multiplication took ten cycles, a division took 29, and the overall performance, taking into account memory delays and other issues, was about 3 MFLOPS. Using the best available compilers, late in the machine's history, FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
programs could expect to maintain about 0.5 MFLOPS.
Memory organization
User programs are restricted to use only a contiguous area of main memory. The portion of memory to which an executing program has access is controlled by the RA (Relative Address) and FL (Field Length) registers which are not accessible to the user program. When a user program tries to read or write a word in central memory at address a, the processor will first verify that a is between 0 and FL-1. If it is, the processor accesses the word in central memory at address RA+a. This process is known as base-bound relocation; each user program sees core memory as a contiguous block words with length FL, starting with address 0; in fact the program may be anywhere in the physical memory. Using this technique, each user program can be moved ("relocated") in main memory by the operating system, as long as the RA register reflects its position in memory. A user program which attempts to access memory outside the allowed range (that is, with an address which is not less than FL) will trigger an interrupt, and will be terminated by the operating system. When this happens, the operating system may create a core dumpCore dump
In computing, a core dump consists of the recorded state of the working memory of a computer program at a specific time, generally when the program has terminated abnormally...
which records the contents of the program's memory and registers in a file, allowing the developer of the program a means to know what happened. Note the distinction with virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...
systems; in this case, the entirety of a process's addressable space must be in core memory, must be contiguous, and its size cannot be larger than the real memory capacity.
All but the first seven CDC 6000 series
CDC 6000 series
The CDC 6000 series was a family of mainframe computers manufactured by Control Data Corporation in the 1960s. It consisted of CDC 6400, CDC 6500, CDC 6600 and CDC 6700 computers, which all were extremely rapid and efficient for their time...
machines could be configured with an optional Extended Core Storage (ECS) system. ECS was built from a different variety of core memory than was used in the central memory. This made it economical for it to be both larger and slower. The primary reason was that ECS memory was wired with only two wires per core (contrast with 5 for central memory), Because it performed very wide transfers, its sequential transfer rate was the same as that of the small core memory. A 6000 CPU could directly perform block memory transfers between a user's program (or operating system) and the ECS unit. Wide data paths were used, so this was a very fast operation. Memory bounds were maintained in a similar manner as central memory — with an RA/FL mechanism maintained by the operating system. ECS could be used for a variety of purposes, including containing user data arrays that were too large for central memory, holding often-used files, swapping, and even as a communication path in a multi-mainframe complex.
Peripheral Processors (PPs)
To handle the 'household' tasks which other designs put in the CPU, Cray included ten other processors, based partly on his earlier computer, the CDC 160ACDC 160A
The CDC 160 and CDC 160-A were 12-bit minicomputers built by Control Data Corporation from 1960 to 1965. The 160 was designed by Seymour Cray - reportedly over a long three-day weekend...
. These machines, called Peripheral Processors, or PPs, were full computers in their own right, but were tuned to performing I/O
Input/output
In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...
tasks and running the operating system. One of the PPs was in overall control of the machine, including control of the program running on the main CPU, while the others would be dedicated to various I/O tasks — quite similarly to I/O channels in IBM mainframe
IBM mainframe
IBM mainframes are large computer systems produced by IBM from 1952 to the present. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their marketshare...
s of the time. When the program needed to perform some sort of I/O, it instead loaded a small program into one of these other machines and let it do the work. The PP would then inform the CPU when the task was complete with an interrupt.
Each PP included its own memory of 4096 12-bit
12-bit
Possibly the best-known 12-bit CPU is the PDP-8 and its relatives, produced in various incarnations from August 1963 to mid-1990. Many ADCs have a 12-bit resolution. Some PIC microcontrollers use a 12-bit word size....
words. This memory served for both for I/O buffering and program storage, but the execution units were shared by 10 PPs, in a configration called the Barrel and slot
Barrel processor
A barrel processor is a CPU that switches between threads of execution on every cycle. This CPU design technique is also known as "interleaved" or "fine-grained" temporal multithreading...
. This meant that the execution units (the "slot") would execute one instruction cycle from the first PP, then one instruction cycle from the second PP, etc. in a round robin fashion. This was done both to reduce costs, and because access to CP memory required 10 PP clock cycles: when a PP accesses CP memory, the data is available next time the PP receives its slot time.
Wordlengths, characters
The central processor had 60-bit60-bit
Computers with 60-bit words include the CDC 6000 series and some of the CDC Cyber series....
words, whilst the peripheral processors had 12-bit
12-bit
Possibly the best-known 12-bit CPU is the PDP-8 and its relatives, produced in various incarnations from August 1963 to mid-1990. Many ADCs have a 12-bit resolution. Some PIC microcontrollers use a 12-bit word size....
words. CDC used the term "byte" to refer to 12-bit entities used by peripheral processors; characters were 6-bit, and central processor instructions were either 15 bits, or 30 bits with a signed 18-bit address field, the latter allowing for a directly addressable memory space of 128K words of central memory (converted to modern terms, with 8-bit bytes, this is 0.94 MB). The signed nature of the address registers limited an individual program to 128K words. (Later CDC 6000-compatible machines could have 256K or more words of central memory, budget permitting, but individual user programs were still limited to 128K words of CM.) Central processor instructions started on a word boundary when they were the target of a jump statement or subroutine return jump instruction, so no-operations were sometimes required to fill out the last 15, 30 or 45 bits of a word.
The 6-bit characters, in an encoding called display code
Display code
Display code is the 6-bit character set used by many computer systems manufactured by Control Data Corporation, notably the CDC 6600 in 1964. The CDC 6000 series, and their followons, had 60 bit words. As such, typical usage packed 10 characters per word....
, could be used to store up to 10 characters in a word. They permitted a character set of 64 characters, which is enough for all upper case letters, digits, and some punctuation. Certainly, enough to write FORTRAN
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
, or print financial or scientific reports. There were actually two variations of the display code
Display code
Display code is the 6-bit character set used by many computer systems manufactured by Control Data Corporation, notably the CDC 6600 in 1964. The CDC 6000 series, and their followons, had 60 bit words. As such, typical usage packed 10 characters per word....
character sets in use, 64-character and 63-character. The 64-character set had the disadvantage that two consecutive ':' (colon) characters might be interpreted as the end of a line if they fell at the end of a 10-byte word. A later variant, called 6/12 display code
Display code
Display code is the 6-bit character set used by many computer systems manufactured by Control Data Corporation, notably the CDC 6600 in 1964. The CDC 6000 series, and their followons, had 60 bit words. As such, typical usage packed 10 characters per word....
, was also used in the Kronos and NOS
NOS (software)
NOS was an operating system with time-sharing capabilities, written by Control Data Corporation in the 1970s....
timesharing systems to allow full use of the ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
character set in a manner somewhat compatible with older software.
With no byte addressing instructions at all, code had to be written to pack and shift characters into words. The very large words, and comparatively small amount of memory, meant that programmers would frequently economize on memory by packing data into words at the bit level.
It is interesting to note that due to the large word size, and with 10 characters per word, it was often faster to process words full of characters at a time — rather than unpacking/processing/repacking them. For example, the CDC COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....
compiler was actually quite good at processing decimal fields using this technique. These sorts of techniques are now commonly used in the 'multi-media' instructions of current processors.
Physical design
The machine was built in a plus-sign-shaped cabinet with a pump and heat exchanger in the outermost 18 in (45.7 cm) of each of the four arms. Cooling was done with Freon circulating within the machine and exchanging heat to an external chilled water supply. Each arm could hold four chassis, each about 8 in (20.3 cm) thick, hinged near the center, and opening a bit like a book. The intersection of the "plus" was filled with cables which interconnected the chassis. The chassis were numbered from 1 (containing all 10 PPUs and their memories, as well as the 12 rather minimal I/O channels) to 16. The main memory for the CPU was spread over many of the chassis. In a system with only 64K words of main memory, one of the arms of the "plus" was omitted.The logic of the machine was packaged into modules about 2.5 in (63.5 mm) square and about 1 in (2.5 cm) thick. Each module had a connector (30 pins, 2 vertical rows of 15) on one edge, and six test points on the opposite edge. The module was placed between two aluminum cold plates to remove heat. The module itself consisted of two parallel printed circuit boards, with components mounted either on one of the boards or between the two boards. This provided a very dense, if somewhat difficult to repair, package with good heat removal that was known as cordwood construction.
Operating system and programming
There was a sore point with the 6600 operating systemOperating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
support — slipping timelines. The machines originally ran a very simple job-control
Batch processing
Batch processing is execution of a series of programs on a computer without manual intervention.Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters...
system known as COS (Chippewa Operating System
Chippewa Operating System
The Chippewa Operating System often called COS was the operating system for the CDC 6600 supercomputer, generally considered the first super computer in the world...
), which was quickly "thrown together" based on the earlier CDC 3000
CDC 3000
The CDC 3000 series computers from Control Data Corporation were mid-1960s follow-ons to the CDC 1604 and CDC 924 systems. Over time, a range of machines were produced - divided into the 'upper 3000 series' and the 'lower 3000 series'. CDC phased out production of the 3000 series in the early 1970s...
operating system in order to have something running to test the systems for delivery. However the machines were intended to be delivered with a much more powerful system known as SIPROS (for Simultaneous Processing Operating System), which was being developed at the company's System Sciences Division in Los Angeles
Los Ángeles
Los Ángeles is the capital of the province of Biobío, in the commune of the same name, in Region VIII , in the center-south of Chile. It is located between the Laja and Biobío rivers. The population is 123,445 inhabitants...
. Customers were impressed with SIPROS's feature list, and many had SIPROS written into their delivery contracts.
SIPROS turned out to be a major fiasco. Development timelines continued to slip, costing CDC major amounts of profit in the form of delivery delay penalties. After several months of waiting with the machines ready to be shipped, the project was eventually cancelled. The programmers who had worked on COS had little faith in SIPROS (likely due largely to not invented here
Not Invented Here
Not invented here is a term used to describe persistent social, corporate, or institutional culture that avoids using or buying already existing products, research, standards, or knowledge because of their external origins. It is normally used in a pejorative sense, and may be considered an...
syndrome) and had continued working on improving COS.
Operating system development
Operating system development
Operating system development is one of the more involved and technical options for a computer hobbyist.A hobby operating system is classified as one with little or no support from other developers.Development begins with an existing operating system...
then split into two camps. The CDC-sanctioned evolution of COS was undertaken at the Sunnyvale, California
Sunnyvale, California
Sunnyvale is a city in Santa Clara County, California, United States. It is one of the major cities that make up the Silicon Valley located in the San Francisco Bay Area...
software development lab. Many customers eventually took delivery of their systems with this software, then known as SCOPE
SCOPE (software)
SCOPE, an acronym for Supervisory Control Of Program Execution, was the name used by the Control Data Corporation for a number of operating system projects in the 1960s.-Variants:* SCOPE for the CDC 3000 series....
(Supervisory Control Of Program Execution). (Some Control Data Field Engineers used to refer to SCOPE as Sunnyvale's Collection Of Programming Errors). SCOPE version 1 was, essentially, dis-assembled COS; SCOPE version 2 included new device and file system support; SCOPE version 3 included permanent file support, EI/200 remote batch support, and INTERCOM time sharing support. SCOPE always had significant reliability and maintainability issues.
The underground evolution of COS took place at the Arden Hills, Minnesota
Arden Hills, Minnesota
As of the census of 2000, there were 9,652 people, 2,959 households, and 2,228 families residing in the city. The population density was 1,087.3 people per square mile . There were 3,017 housing units at an average density of 339.9 per square mile...
assembly plant. MACE ([Greg] Mansfield And [Dave] Cahlander Executive) was written largely by a single programmer in the off-hours when machines were available. Its feature set was essentially the same as COS and SCOPE 1. It retained the earlier COS file system, but made significant advances in code modularity to improve system reliability and adaptiveness to new storage devices. MACE was never an official product, although many customers were able to wrangle a copy from CDC.
MACE was later used as the basis of Kronos, named after the Greek god of time
Chronos
In Greek mythology, Chronos in pre-Socratic philosophical works is said to be the personification of time. His name in Greek means "time" and is alternatively spelled Chronus or Khronos.Chronos was imagined as an incorporeal god, serpentine in form, with three heads—those of a man, a bull, and...
. The main marketing reason for its adoption was the development of its TELEX time sharing feature and its BATCHIO remote batch feature. Kronos continued to use the COS/SCOPE 1 file system with the addition of a permanent file feature.
An attempt to unify the SCOPE and Kronos operating system products produced NOS
NOS (software)
NOS was an operating system with time-sharing capabilities, written by Control Data Corporation in the 1970s....
, (Network Operating System). NOS was intended to be the sole operating system for all CDC machines, a fact CDC promoted heavily. Many SCOPE customers remained software-dependent on the SCOPE architecture, so CDC simply renamed it NOS/BE (Batch Environment), and were able to claim that everyone was thus running NOS. In practice, it was far easier to modify the Kronos code base to add SCOPE features than the reverse.
The assembly plant environment also produced other operating systems which were never intended for customer use. These included the engineering tools SMM for hardware testing, and KALEIDOSCOPE, for software smoke testing. Another commonly used tool for CDC Field Engineers during testing was MALET (Maintenance Application Language for Equipment Testing), which was used to stress test components and devices after repairs and/or servicing by engineers. Testing conditions often used hard disk packs and magnetic tapes which were deliberately marked with errors to determine if the errors would be detected by MALET and the engineer.
External links
- Neil R. Lincoln with 18 Control Data Corporation (CDC) engineers on computer architecture and design, Charles Babbage InstituteCharles Babbage InstituteThe Charles Babbage Institute is a research center at the University of Minnesota specializing in the history of information technology, particularly the history since 1935 of digital computing, programming/software, and computer networking....
, University of Minnesota. Engineers include Robert Moe, Wayne Specker, Dennis Grinna, Tom Rowan, Maurice Hutson, Curt Alexander, Don Pagelkopf, Maris Bergmanis, Dolan Toth, Chuck Hawley, Larry Krueger, Mike Pavlov, Dave Resnick, Howard Krohn, Bill Bhend, Kent Steiner, Raymon Kort, and Neil R. Lincoln. Discussion topics include CDC 1604CDC 1604The CDC 1604 was a 48-bit computer designed and manufactured by Seymour Cray and his team at the Control Data Corporation. The 1604 is known as the first commercially successful transistorized computer. Legend has it that the 1604 designation was chosen by adding CDC's first street address to...
, CDC 6600, CDC 7600CDC 7600The CDC 7600 was the Seymour Cray-designed successor to the CDC 6600, extending Control Data's dominance of the supercomputer field into the 1970s. The 7600 ran at 36.4 MHz and had a 65 Kword primary memory using core and variable-size secondary memory...
, CDC 8600CDC 8600The CDC 8600 was the last of Seymour Cray's supercomputer designs while working for the Control Data Corporation. The "natural successor" to the CDC 6600 and CDC 7600, the 8600 was intended to be about 10 times as fast as the 7600, already the fastest computer on the market.Development started in...
, CDC STAR-100CDC STAR-100The STAR-100 was a vector supercomputer designed, manufactured, and marketed by Control Data Corporation . It was one of the first machines to use a vector processor to improve performance on appropriate scientific applications....
and Seymour CraySeymour CraySeymour Roger Cray was an American electrical engineer and supercomputer architect who designed a series of computers that were the fastest in the world for decades, and founded Cray Research which would build many of these machines. Called "the father of supercomputing," Cray has been credited...
. - Parallel operation in the Control Data 6600, James Thornton
- Presentation of the CDC 6600 and other machines designed by Seymour Cray – by C. Gordon BellGordon BellC. Gordon Bell is an American computer engineer and manager. An early employee of Digital Equipment Corporation 1960–1966, Bell designed several of their PDP machines and later became Vice President of Engineering 1972-1983, overseeing the development of the VAX...
of Microsoft Research (formerly of DEC)