ICL Minicomputers

1 Version 3: October 2015 ICL minicomputers. Historical background. Established in 1968, ICL was an amalgam of ICT and the mainframe computer interests of English Electric. ICT had previously acquired the mainframe interests of EMI and Ferranti. In turn, English Electric had, by 1967, acquired the mainframe interests of Leo, Marconi and Elliott Automation. Thus, by a complex process of mergers and take-overs, in 1968 ICL became the only major UK manufacturer of mainframe computers. The ICL 1900 range, launched in 1964, was the company’s first major initiative. This was followed ten years later by the 2900 range, which itself was superseded by the Series 39 in the mid-1980s. ICL started to have links with Fujitsu in 1981. Eventually Fujitsu acquired ICL and, in June 2001, Fujitsu decided to dispense with the name ICL. At that point, ICL employed 19,200 people in Europe, the Middle East and Africa, over 10,000 of whom were in the UK. In 2002 the residue of the ICL company was re-branded as Fujitsu’s European Services arm. Back in the 1970s, ICL was actively interested in a broad range of commercially-oriented applications involving both large and small computers – some of the latter coming within the definition of minicomputer. Three particular ICL products are considered as minicomputers and are described later in this section. These are the ICL DRS/20, the ICL System Ten and the ICL System 25 minicomputers. The sub-section on the DRS/20 begins by reviewing the underlying world-wide technological innovations that were driving the whole of the minicomputer market area. Finally, it is worth observing that ICL did not really interest itself in smaller computers for real- time industrial process control or on-line defence-related applications. From 1968 onwards these specialist fields were left to the small systems divisions of Ferranti and Elliott- Automation, the latter becoming part of GEC in 1968. Post-1968 minicomputers designed under the GEC and Ferranti labels are in separate sections of the Our Computer Heritage website. The ICL DRS/20 description starts on the next page. Descriptions for the ICL System 10 and System 25 will follow but have not yet been uploaded at the time of writing. 1 2 ICL’s DRS 20 Series – Distributed Resource Systems Product Overview Contents. Introduction page 3 2. The Distributed Resource Architecture- DRA page 3 2.1 Early Microprocessors 2.2 Microprocessor Software Development Tools 2.3 DRA-the basic concept 2.3.1 Hardware Architecture 2.3.2 Software Architecture 3. Early Hardware Products page 8 3.1 Model 10 3.2 Model 40 3.3 Model 50 3.4 Peripheral Systems Options 3.5 Additional Models ( announced mid-1982) 3.5.1 Model 20 3.5.2. Model 25 3.6 Product Packaging/Styling/Colours 3.7 Microlan 4. Software Products page 10 4.1 R-Mode 4.2 N-Mode 4.3 Distributed Text Manager (DTM) 4.4 Communications & Networking 2 3 4.5 CP/M 5. Derived Products and later DRS20 Models page 12 5.1 Retail POS Controllers 5.2 Interactive Terminal systems 5.3 DRS20 – 100 Series 5.4 Other Software/Applications Program Products 6. Pricing, Commercial and Marketing Indicators page 13 6.1 Price Positioning 6.1.1 System Product pricing examples 6.1.2 Software pricing examples 6.2 Market Positioning 6.3 Business achievement 7. Reference sources page 16 1. Introduction The DRS20 Series of desktop Intelligent Workstations, and pedestal-cabinet packaged File, Network, and Communications Servers were the first members of a new ICL family of Distributed Processing System products, announced in September 1981. They were aimed at the (then) emerging, and subsequently burgeoning, markets for Departmental Computing, Distributed Processing, Networked Word Processing and Office Systems, interlinked with larger centralized mainframe Corporate computer systems via a variety of (again emerging, but later industry-standardized) Local- and Wide Area Networks communications technologies, standards and protocols. During the 1970’s microcomputer technology was fast developing, together with associated software and application development tools, to the point where single- user, desktop intelligent workstations and prototype “personal computers” , with screen/keyboard and “floppy disk” storage, were becoming a practical proposition at an affordable price ( “... purchasable for about one quarter of a programmer’s annual salary. Quite simply -by mid 1970’s- it was no longer necessary to share computing resources.” - Dr. Gary A. Kildall - Digital Research Inc. – pub. Byte Magazine. June 1981). 3 4 The DRS20 series derived from development projects and products acquired by ICL following its take- over of Singer Business Machines (SBM) in 1976, and in particular, the plant and development labs. in Utica, New York, home of the Singer 1500 ( formerly Cogar C4) Intelligent Terminal /Data Capture product ranges. These products were already spearheading the trend towards the distribution of computing resources away from a centralized “Data Processing Centre” and into end user departments, and remote locations in large multi- location Corporations or Public Services organisations, and into the smaller businesses and offices of multifarious mid –sized organisations worldwide. The generic product branding terminology for the new ICL family of products – “Distributed Resource Systems” (DRS) – was chosen to reflect not only the market and user segments the products were targeting, but also the system’s architectural design and hardware/software structures. As described below, multiple microprocessor subsystems themselves were “distributed” internally within a system “node” or unit to provide the sort of end-user application performance that could only previously have been delivered by a much faster, complex and hence more costly, shared minicomputer single central processors. 2. The Distributed Resource Architecture - DRA 2.1 Early Microprocessors. To appreciate the hardware and software architecture of DRS20, one must first consider the state of development and sophistication of microcomputers, and their related software development tools, at that period i.e. during the 1970’s. Intel had introduced its first “commercial” 4-bit microprocessor family- the MCS-4 with the 4004 CPU - in 1971. This was followed in 1972 by the 8-bit “8000” family, with its 8008 CPU, and, subsequently, the higher performance 8080 (1974) and 8085 (1976) CPUs, together with the MCS-85 family of support chips for memory, peripheral I/O controllers etc. These latter CPUs could address 64Kb of memory (compared to just 16Kb of the 8008) with a Bus width of 8-bits (data) / 16- bits (addressing) structure – enough to become the basis for early microcomputer systems. (eg 8080 was used in the Altair 8800 System – generally regarded as one of the first practical, if somewhat limited, desktop microcomputers.) Other comparable microprocessors were being introduced at the time, such as Zilog Z80, TI’s TMS1000 and Motorola 68000, but Intel was emerging as the market leader and computer systems developers’ supplier of choice – especially in USA. But compared to contemporary minicomputers ( eg DEC VAX’s), and even small mainframe processors, the performance of these micros was still relatively modest. For example: 8080: Clock rate - 2 4 5 MHz, delivering 0.29 MIPS. For the 8085: Clock rate – 3MHz and 0.37 MIPS. Enough , perhaps, for a single –user, single- processing , simple application on a DIY home- build micro., but hardly enough to support multi-user, multi-processing , “serious” transaction processing systems in the corporate Data Processing/ Information Processing world? Note also that 16-bit microprocessors, with faster Clock rates, and larger addressable memories, did not start appearing until the late 1970s. Intel’s MCS-86 Family , with the 8086 CPU (up to 10 MHz with 0.75 MIPS; Bus width- 16 bits data, 20 bits address; 1 Mb memory), and the 8088* CPU ( 8MHz with 0.66 MIPS; Bus-width – 8 bits data, 20bits address; 1 Mb memory) were not introduced until 1978 and 1979 respectively. (*The 8088 was used in IBM’s first PC, launched in August 1981). 8088 also provided forward compatibility from Intel’s earlier 8-bit family, using the common 8 -bit data bus width. This latter facility subsequently proved valuable for the evolutionary development and enhancement of the initial DRS20 design, which, in its first manifestations, used the Intel 8-bit family microprocessors and support chips, but later moved to 16 –bit processors. 2.2 Microprocessor Software Development Tools. Thus, the choice for new product hardware developments at Singer’s (later, ICL’s) Utica facility in the mid 1970s was, not surprisingly, the Intel 8-bit microprocessor family – and particularly 8085 CPU. In addition and in parallel, a whole set of software development tools and products were emerging to enable the more effective implementation of “proper” DP /IT systems on these Intel microprocessors; most notably from DRI ( Digital Research Inc.) with its pioneering CP/M operating systems software. Developed during 1973/74, the original 8- bit CP/M provided three main components: BIOS (Basic Input /Output ); BDOS ( Basic Disc Operating System); and CCP ( Console Command Processor), designed to run on a minimum hardware configuration comprising an ASCII terminal (eg.Teletype or Video/Keyboard); an 8080 or 8085 microprocessor CPU with min. 16k RAM; at least one Floppy Disk drive ( originally 8”). Not very sophisticated, but enough for system developers to start building viable single-user application systems. Later versions of the CP/M family, particularly for 16-bit micros such as 8086 /8088, evolved to support other disc storage subsystems (eg 5.25 in. Floppies, and 8” and 5 ¼” hard disc drives – “Winchester” technology – of varying capacities). Multi- programming (MP/M), and Concurrent Application execution (CCP/M) versions followed, but not until early 1980’s. CP/NET, which distributed operating system functions throughout a network of microprocessors, first appeared in late 1980.

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