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ICL Brochures
English Electric Computers
System 4-70
A member of the micro-integrated System 4 family
Fully-integrated electronics
System 4-70 is a member of the System 4 family, the first computer family in the world in which all processors use fully-integrated circuitry. One monolithic circuit performs the functions of transistors, diodes, capacitors, resistors, and their interconnections. For linking groups of circuits 4-70 uses multilayer platters with printed circuitry itself designed by computer. The platters, which combine logical connections and power supply lines, eliminate much of the voluminous rack-wiring that persists in other computer ranges.
Fully-integrated circuits bring you these positive advantages:
Reliability. Semi-conductor integrated circuits obviate those weak points inherent in the mounting of discrete components. And manufacturing the circuits in a controlled environment brings out their full intrinsic reliability.
Cost. They are ideal for mass-production methods and are thus cheaper to make. This is reflected in the remarkable cost/performance value of System 4-70.
Space. Fully-integrated circuits are exceptionally small. Your System 4-70 processor, as a result, is very compact for its power.
Speed. The smallness of fully-integrated circuits makes them intrinsically faster and this has been brilliantly exploited in the outstanding arithmetic speeds of the 4-70 processor.
ICL
On 10 August 1968 the business of English Electric Computers Limited was merged with that of International Computers Limited (ICL).
Since that date all products and services described in this publication are supplied by ICL
A computer for the most demanding commercial and scientific applications
System 4-70 meets the most exacting computational requirements of large scale commercial data processing and research. There are four separate sets of registers in the 4-70 scratchpad with an access time of 120 nanoseconds. Each logical aspect has its own independent storage system, eliminating bottlenecks and facilitating a remarkable throughput.
System 4-70 recognises the need for linking different types of computer or to change computers without the heavy burden of reprogramming. 4-70 information and instruction code are compatible with those of other leading international suppliers. Magnetic tape and disc files are readily interchangeable.
Powerful data handling and very fast floating point commands are included in the 4-70 set of 144 instructions. Operations may be carried out on variable length alphanumeric character streams where the amount of calculation on the information being handled is comparatively low, or in binary words where the calculations are more demanding.
Instructions are variable in length and deal compactly with the different needs. They are all implemented by micro-programs stored in a Read-only store and their speed is enhanced by instruction pre-fetching during the execution of the previous instruction.
System 4-70 can run several full-scale data processing programs concurrently, Multi-programming is an essential feature of the 4-70. It was developed through English Electric's experience of multi-programming on the Leo 3 range and on KDF 9, and is implemented through a combination of hardware and software. Independently programmed major jobs can be run simply and efficiently at one time because of these 4-70 features:
a fast interrupt system
registers located in a scratchpad store (access time 120 nanoseconds) full store protection for 14 programs at a time
a program priority control system built into the Executive software.
High information transfer rates
With a data transfer rate of up to 4 million bytes per second, 4-70 eliminates the usual bottleneck in input/output. This extremely high rate is made possible through independently operating multiplexor and selector channels. By operating concurrently with one another and with computing, these Channels enable over 500 different peripheral operations to take place at the same time.
Multiplexor Channels control up to 16 groups of devices concurrently, by interleaving the data received. Three multiplexors can be fitted to the 4-70. Single-channel selectors control only one device at a time although four may be connected. Multi-channel selectors can control eight devices concurrently. The selector channels control and assemble into words all the information for transfer to and from store. Store accesses are thus minimised and no demands are made on the capacity of the arithmetic unit. A special input/output control enables instructions to be chained together and obeyed by the multiplexor or selector channels independently of the main program.
Maximum input/output capabilities
Overall transfer rate in bytes per second Input/output devices other than remote stations on a transmission network
Remote stations
Number of device control units
Concurrent multiplexed operations
Concurrent selector channels
Simultaneous transfer operations
Large and varied storage capabilities
Main core store
System 4-70 has a minimum capacity of 65, 536 bytes. It can be increased in stages to a maximum of 1, 048, 576. Four bytes are accessed and regenerated in one store cycle of 0 · 9 microsecond, but an effective cycle time of 650 nanoseconds. is achieved through interleaving. Odd and even addresses are accessed via separate highways so that both are available at the same time. A base and displacement addressing system allows very large stores to be addressed directly.
Scratchpad stores
System 4-70 bases its fast computational and interrupt speeds on a very fast micro-magnetic store with a cycle time of 250 nanoseconds for 4 bytes. This is used for arithmetic, base addressing, indexing, floating point, and interrupt servicing. Independent 250 nanosecond scratchpad stores are used for servicing the multichannels.
Read-only store
This holds the micro-programming of the individual instructions and makes it possible to implement the most complex facilities with straightforward easily maintained circuitry.
Mass core store
System 4-70 allows for the addition of modules of inexpensive, slower speed core store to hold data and programs.
Random access backing store
System 4-70 has a variety of random access storage devices which enable it to meet the largest storage requirements. These devices include Replaceable Disc units with capacities of '7·25 million bytes, and Discfiles holding 350 or 700 million bytes. Many of them can be linked at one time to System 4-70 through the selector channels. The total on-line capacity is vast.
Magnetic tape storage
System 4-70 can at the same time handle both seven- and nine-track magnetic tape units with speeds of up to 120, 000 bytes per second which is the equivalent of 240, 000 digits per second. This flexibility means that the 4-70 is compatible simultaneously with existing seven-track tape systems and the latest nine-track systems. Duplex device control units make it possible to drive one magnetic tape unit through two separate channels as convenience dictates. A linked pair of magnetic tape device control units can simultaneously read or write information from or to any two of 16 tape units.
System 4·70
This is an example of the powerful System 4-70 data processing system. The use of micro-integrated circuits has resulted in a processor of exceptionally small size - even the tallest units are only 5 feet 2 inches high.
a Central processor
b Magnetic tape units
c Magnetic tape control units
d Paper tape reader
e Paper tape punch
f Replaceable disc store
g Line printer
h Discfile auxiliary unit
j Card reader
k Control desk with standard control typewriter
m Discfile
n Discfile control unit
o Replaceable disc store control unit
Comprehensive software
To give maximum utilisation of a System 4-70 installation, its outstanding technology has been matched by comprehensive software and operating systems. The operating systems cover all 4-70 configurations and provide flexible modular program facilities to do each job in the most efficient and economical manner. It will be possible to develop and run installation programs and employ the vast computing potential made available by multi-programming, more quickly than ever before.
System 4-70 provides both the commercial and scientific user with all the languages most widely employed today. The initial complement of Cobol, Fortran, Algol, Apt, and Cleo will be supplemented by other languages as they gain international acceptance. These efficient programming facilities enable work to be programmed and mounted quicker, and programs to be transferred easily from existing equipment.
Modular software packages
Software complements for small configurations are subsets of those for larger configurations, and can be gradually built up as the configuration is expanded. This ensures not only that the right software is available, but that storage and peripheral requirements for a particular user are not excessive.
Easy program development
Programs may be written in a variety of source languages and tested in small sections or in larger combinations of source text. Facilities are provided to combine independently compiled sections to form a complete binary program ready for production use.
System 4-70 software facilities include
Usercode assembly system. A convenient machine oriented assembly system using mnemonic instructions with symbolic addressing and input-output macros.
Executive. Undertakes the management of the complete system including such functions as Job control, Store allocation, Input-Output control, Multi-programming, and Operator communication.
Program trials system. A program development facility providing, by means of parameters, a variety of testing and diagnostic aids capable of being invoked by the User at specified points in a program.
Media conversion generator. To produce programs to take input data from any medium and output the data to any medium in a format specified by the user.
Communication control routine. A comprehensive control routine for communication lines, with facilities for error detection and re-transmission.
System library maintenance. To create, amend, operate, and edit program libraries stored on magnetic tape and other media.
Library subroutines. Subroutines to perform basic programming functions which may be incorporated in the machine code program during compilation.
Cleo compiler. Implementation of the highly successful language introduced on Leo 3.
Cobol compiler. A full Cobol implementation including sort, report writer, and random access input-output.
Algol compiler. Implementation of Algol 60 including all those facilities provided with KDF 9.
Fortran compiler. A full implementation of Fortran IV including extended arithmetic and data types.
Apt compiler. A compiler for the numerical control of automatically programmed machine tools.
CSL simulation language compiler. For the construction of mathematical models to solve scientific and business problems.
File control routines. Provide complete control over input-output operations including multiple buffering areas, restart check points, and multi-file control. Sort program generator. Generates either generalised or special programs for sorting or merging.
Report program generator. Incorporates a simple language providing facilities for writing programs to produce reports.
Pert. Two packages are provided to analyse Pert networks - Time, and Resource Allocation.
Linear programming (Transportation). A program suite to solve transportation problems, yielding solutions in source or destination order. New problems can be started from existing solutions.
Linear programming (Simplex). A program suite to check data, calculate solutions, and print answers. The solution consists of values of basic variables, objective function, and shadow costs on run-basis variables.
Matrix scheme. Facilities for manipulating matrices, matrix arithmetic, automatic storage, and for handling diagonal and symmetric matrices.
A computer for the largest and most complex jobs
Commerce and Government
As a very large general purpose computer, System 4-70 will handle a wide variety of high volume clerical work, running up to 14 programs at a time. It effectively acts as several large computers, working back to back, with all the benefits of shared storage and facilities. The very large number of peripheral devices that can run concurrently on System 4-70 and the even larger number that are accessible at any one time ensure that a multi-programmed system will never be short of input/output capacity. Also, the very large core store that is available at reasonable cost makes it possible to store a number of very large programs and their related data without constraints.
System 4-70 is ideal for large scale work. It is an excellent tool too for the management sciences, for design automation planning, and the forecasting and engineering calculations which most large organisations have as a secondary load.
Science and research
System 4-70 is a very powerful scientific research tool. It will hold a large variety of programs, complete and under development, in a random access store. Powerful software for handling such a program bank has already been shown in operation on the KDF 9 computers.
For the University which requires a computer that will cope equally well with research in depth, training in numerical science, and the administrative work of the community, System 4-70 offers the wide variety of facilities, hardware and software, that is needed.
Satellite applications
Operated as the controller of a network of interconnected computers, System 4-70 will pass information and allocate tasks to subservient machines. By multi-programming, it can itself at the same time shoulder the heaviest tasks in the network of scientific and management science computation, and display the results direct to management. Where it is required to off-load data reduction or printing tasks, a smaller member of the family, the 4-30, can provide all that is necessary to take the load on-line or off-line and on-site or remotely.
Communication systems
4-70 can be used as the centre of a data transmission network, controlling remote stations fitted with such devices as enquiry stations and automatic data capturing devices. System 4-70 offers immediate response to enquiries however complex the calculation they require. A very considerable number and variety of remote devices can be handled at any one time.
Input/output devices
Peripheral equipment covering the full range of input-output, storage, and communication requirements are available with System 4-70. There is a standard interface. Any System 4 peripheral device can be used with any System 4 processor and peripherals can be added on site by simply plugging in.
Paper tape units
Reader Punch
1500 characters per second 150 characters per second
Card units
Readers 800 or 1435 cards per minute Punches 100 or 300 cards per minute
Line printers
Medium speed model (with optional double numeric barrel) 750 lines per minute 1500 lines per minute
High speed model (with optional double numeric barrel) 1350 lines per minute 2700 lines per minute
Magnetic tape units
7-track Up to 60, 000 characters per second
9-track 30, 000, 60, 000 or 120, 000 bytes per second
Random access devices
Replaceable disc store Capacity 7·25 million bytes
Disc file Capacity 350 or 700 million bytes
Magnetic drum Capacity 2 million bytes
Document readers
Magnetic ink character reader 1500 documents per minute
Communication equipment
Equipment for linking processors to other processors Equipment for linking processors to enquiry stations Equipment for linking processors to data transmission lines
In addition Lector 2 is available. It reads documents containing bar marks in significant positions. The marks may be made by hand, by computer printer or by address plate. The operating speed depends on form size, which may vary from 3 in by 5 in to 10 in by 16 in. Lector 2 is also available in off-line form.
English Electric Computers Limited An English Electric Company
Head Office and Main Factory
Kidsgrove, Stoke-on-Trent, Staffordshire Kidsgrove 3511 021-643 9721
South West
36/38 Baldwin Street, Bristol t Bristol 21406 STD OBR 2
North West
St. Ann's House, Alderley Road, Wilmslow, Cheshire Wilmslow 27461
North East
Tithe House, Horsforth, Nr. Leeds, Yorkshire Horsforth 4678 STD OWR 34
Marconi House, Melbourne Street Newcastle-upon-Tyne 1, NE1 2AA
0632 610863
Furnival House, Furnival Gate
Sheffield 1, S1 4QP
0742 79483
Scotland and Ireland
West Coates House, 90 Haymarket Terrace Edinburgh 12 031-337 5371
Bureau Division
Kidsgrove Bureau
Kidsgrove, Stoke-on-Trent, Staffordshire Kidsgrove 3511
London Bureau
Hartree House, Queensway, London W2 O1-229 9451 · Bristol Bureau
36/38 Baldwin Street, Bristol 1
Bristol 21406 STD OBR 2
Training Division
Radley House, 35/39 South Ealing Road, London W5 O1-567 7262 and 6066
Overseas
Australia
Australian Computers Pty. Ltd., ADC House, 77 Pacific Highway, North Sydney, New South Wales Cables: Leotronic, Sydney. Tel 929-8155
320/322 St. Kilda Road, Melbourne 5C1, Victoria Cables: Leotronic, Melbourne. Tel 697191
New Zealand
English Electric-Leo Data Systems Ltd. GPO Box 3667, Wellington
Cables: Leodata, Wellington, NZ. Tel 55-640
South Africa
English Electric Computers South Africa (Pty.) Ltd. PO Box 10987, Johannesburg
Cables: Enelectico, Johannesburg. Tel 836-5286
The policy of English Electric Computers Limited is one of continuous development and improvement of its products and services. The right is therefore
reserved to alter or amend the information contained in this publication without notice.
DP254/4 (copyright all rights reserved
Printed in England by Adams Bros. & Shslrcllow Ltd.
Marketing Head Office Computer House, Euston Centre, London NW1 01-387 7030