IBM 2067
   HOME

TheInfoList



OR:

The IBM System/360 Model 67 (S/360-67) was an important
IBM mainframe IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the large computer market. Current mainframe computers in IBM's line of business computers are developments of the basic design of th ...
model in the late 1960s.''IBM System/360 Model 67 Functional Characteristics''
Third Edition (February 1972), IBM publication GA27-2719-2
Unlike the rest of the S/360 series, it included features to facilitate
time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence ...
applications, notably a Dynamic Address Translation unit, the "DAT box", to support
virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...
, 32-bit addressing and the 2846 Channel Controller to allow sharing channels between processors. The S/360-67 was otherwise compatible with the rest of the S/360 series.


Origins

The S/360-67 was intended to satisfy the needs of key
time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence ...
customers, notably
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the m ...
(where
Project MAC Computer Science and Artificial Intelligence Laboratory (CSAIL) is a research institute at the Massachusetts Institute of Technology (MIT) formed by the 2003 merger of the Laboratory for Computer Science (LCS) and the Artificial Intelligence Lab ...
had become a notorious IBM sales failure), the
University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...
, General Motors,
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial Research and development, research and scientific developm ...
,
Princeton University Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...
, the Carnegie Institute of Technology (later Carnegie Mellon University), and the Naval Postgraduate School. In the mid-1960s a number of organizations were interested in offering interactive computing services using
time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence ...
. At that time the work that computers could perform was limited by their lack of real memory storage capacity. When IBM introduced its System/360 family of computers in the mid-1960s, it did not provide a solution for this limitation and within IBM there were conflicting views about the importance of time-sharing and the need to support it. A paper titled ''Program and Addressing Structure in a Time-Sharing Environment'' by
Bruce Arden Bruce Wesley Arden ( – ) was an American computer scientist. Arden enlisted in the U.S. Navy during World War II (1944-1946) as a Radar Technician Third Class in California, Chicago, and Kodiak, Alaska. He graduated from Purdue University ...
,
Bernard Galler Bernard A. Galler ( in Chicago – in Ann Arbor, Michigan) was an American mathematician and computer scientist at the University of Michigan who was involved in the development of large-scale operating systems and computer languages includi ...
, Frank Westervelt (all associate directors at the University of Michigan's academic Computing Center), and Tom O'Brian building upon some basic ideas developed at the Massachusetts Institute of Technology (MIT) was published in January 1966. The paper outlined a
virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...
architecture using dynamic address translation (DAT) that could be used to implement time-sharing. After a year of negotiations and design studies, IBM agreed to make a one-of-a-kind version of its S/360-65 mainframe computer for the University of Michigan. The S/360-65M would include dynamic address translation (DAT) features that would support
virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...
and allow support for time-sharing. Initially IBM decided not to supply a time-sharing operating system for the new machine. As other organizations heard about the project they were intrigued by the time-sharing idea and expressed interest in ordering the modified IBM S/360 series machines. With this demonstrated interest IBM changed the computer's model number to S/360-67 and made it a supported product. When IBM realized there was a market for time-sharing, it agreed to develop a new time-sharing operating system called IBM Time Sharing System (TSS/360) for delivery at roughly the same time as the first model S/360-67. The first S/360-67 was shipped in May 1966. The S/360-67 was withdrawn on March 15, 1977. Before the announcement of the Model 67, IBM had announced models 64 and 66, DAT versions of its 60 and 62 models, but they were almost immediately replaced by the 67 at the same time that the 60 and 62 were replaced by the 65.


Announcement

IBM announced the S/360-67 in its August 16, 1965 "blue letters" (a standard mechanism used by IBM to make product announcements). IBM stated that: * "Special bid restrictions have been removed from the System/360 Model 67" (i.e., it was now generally available) * It included "multiprocessor configurations, with a high degree of system availability", with up to four processing units hile configurations with up to four processors were announced, only one and two processors configurations were actually builtref name=IBM-S360-67-FuncChar/> * It had "its own powerful operating system... heTime Sharing System monitor (TSS)" offering "virtually instantaneous access to and response from the computer" to "take advantage of the unique capabilities of a multiprocessor system" * It offered "dynamic relocation of problem programs using the dynamic address translation facilities of the 2067 Processing Unit, permitting response, within seconds, to many simultaneous users"


Virtual memory

The S/360-67 design added a component for implementing virtual memory, the "DAT box" (Dynamic Address Translation box). DAT on the 360/67 was based on the architecture outlined in a 1966 '' JACM'' paper by Arden, Galler, Westervelt, and O'Brien and included both segment and page tables. The Model 67's virtual memory support was very similar to the virtual memory support that eventually became standard on the entire
System/370 The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path ...
line. The S/360-67 provided a 24- or 32-bit address space – unlike the strictly 24-bit address space of other S/360 and early S/370 systems, and the 31-bit address space of S/370-XA available on later S/370s. The S/360-67 virtual address space was divided into ''pages'' (of 4096 bytes) grouped into ''segments'' (of 1 million bytes); pages were dynamically mapped onto the processor's real memory. These S/360-67 features plus reference and change bits as part of the storage key enabled operating systems to implement
demand paging In computer operating systems, demand paging (as opposed to anticipatory paging) is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only if an attempt is mad ...
: referencing a page that was not in memory caused a
page fault In computing, a page fault (sometimes called PF or hard fault) is an exception that the memory management unit (MMU) raises when a process accesses a memory page without proper preparations. Accessing the page requires a mapping to be added t ...
, which in turn could be intercepted and processed by an operating system
interrupt handler In computer systems programming, an interrupt handler, also known as an interrupt service routine or ISR, is a special block of code associated with a specific interrupt condition. Interrupt handlers are initiated by hardware interrupts, softw ...
. The S/360-67's virtual memory system was capable of meeting three distinct goals: * Large address space. It mapped physical memory onto a larger pool of virtual memory, which could be dynamically swapped in and out of real memory as needed from random-access storage (typically: disk or drum storage). * Isolated OS components. It made it possible to remove most of the operating system's memory footprint from the user's environment, thereby increasing the memory available for application use, and reducing the risk of applications intruding into or corrupting operating system data and programs. * Multiple address spaces. By implementing multiple virtual address spaces, each for a different user, each user could potentially have a private
virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...
. The first goal removed (for decades, at least) a crushing limitation of earlier machines: running out of physical storage. The second enabled substantial improvements in security and reliability. The third enabled the implementation of true
virtual machines In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hard ...
. Contemporary documents make it clear that full hardware virtualization and virtual machines were ''not'' original design goals for the S/360-67.


Features

The S/360-67 included the following extensions in addition to the standard and optional features available on all S/360 systems: * Dynamic Address Translation (DAT) with support for 24 or 32-bit virtual addresses using segment and page tables (up to 16 segments each containing up to 256 4096 byte pages) * Extended PSW Mode that enables additional interrupt masking and additional control registers * High Resolution Interval Timer with a resolution of approximately 13 microseconds * Reference and change bits as part of storage protection keys * Extended Direct Control allowing the processors in a duplex configuration to present an external interrupt to the other processor * Partitioning of the processors, processor storage, and I/O channels in a duplex configuration into two separate subsystems * Floating Addressing to allow processor storage in a partitioned duplex configuration to be assigned consecutive real memory addresses * An IBM 2846 Channel Controller that allows both processors in a duplex configuration to access all of the I/O channels and that allows I/O interrupts to be presented to either processor independent of what processor initiated the I/O operation * Simplex configurations can include 7 I/O channels, while duplex configurations can include 14 I/O channels * Three new supervisor-state instructions: Load Multiple Control (LMC), Store Multiple Control (SMC), Load Real Address (LRA) * Two new problem-state instructions: Branch and Store Register (BASR), and Branch and Store (BAS) * Two new program interruptions: Segment translation exception (16) and page translation exception (17) The S/360-67 operated with a basic internal cycle time of 200 nanoseconds and a basic 750 nanosecond magnetic core storage cycle, the same as the S/360-65. The 200 ns cycle time put the S/360-67 in the middle of the S/360 line, between the Model 30 at the low end and the Model 195 at the high end. From 1 to 8 bytes (8 data bits and 1 parity bit per byte) could be read or written to processor storage in a single cycle. A 60-bit parallel adder facilitated handling of long fractions in floating-point operations. An 8-bit serial adder enabled simultaneous execution of floating point exponent arithmetic, and also handled decimal arithmetic and variable field length (VFL) instructions.


New components

Four new components were part of the S/360-67: * 2067 Processing Unit Models 1 and 2, * 2365 Processor Storage Model 12, * 2846 Channel Controller, and * 2167 Configuration Unit. These components, together with the 2365 Processor Storage Model 2, 2860 Selector Channel, 2870 Multiplexer Channel, and other System/360 control units and devices were available for use with the S/360-67. Note that while Carnegie Tech had a 360/67 with an IBM 2361 LCS, that option was not listed in the price book and may not have worked in a duplex configuration.


Basic configurations

Three basic configurations were available for the IBM System/360 model 67: * Simplex—one IBM 2067-1 processor, two to four IBM 2365-2 Processor Storage components (512K to 1M bytes), up to seven data channels, and other peripherals. This system was called the IBM System/360 model 67-1. * Half-duplex—one IBM 2067-2 processor, two to four IBM 2365-12 Processor Storage components (512K to 1M bytes), one IBM 2167 Configuration Unit, one or two IBM 2846 Channel Controllers, up to fourteen data channels, and other peripherals. * Duplex—two IBM 2067-2 processors, three to eight IBM 2365-12 Processor Storage components (768K to 2M bytes), one IBM 2167 Configuration Unit, one or two IBM 2846 Channel Controllers, up to fourteen data channels, and other peripherals. A half-duplex system could be upgraded in the field to a duplex system by adding one IBM 2067-2 processor and the third IBM 2365-12 Processor Storage, unless the half-duplex system already had three or more. The half-duplex and duplex configurations were called the IBM System/360 model 67-2.


Operating systems

When the S/360-67 was announced in August 1965, IBM also announced
TSS/360 The IBM Time Sharing System TSS/360 is a discontinued early time-sharing operating system designed exclusively for a special model of the System/360 line of mainframes, the Model 67. Made available on a trial basis to a limited set of custom ...
, a time-sharing operating system project that was canceled in 1971 (having also been canceled in 1968, but reprieved in 1969). IBM subsequently modified TSS/360 and offered the TSS/370 PRPQ for three releases before cancelling it. IBM's failure to deliver TSS/360 as promised opened the door for others to develop operating systems that would use the unique features of the S/360-67 MTS, the
Michigan Terminal System The Michigan Terminal System (MTS) is one of the first time-sharing computer operating systems.. Developed in 1967 at the University of Michigan for use on IBM S/360-67, S/370 and compatible mainframe computers, it was developed and used by a con ...
, was the time-sharing operating system developed at the University of Michigan and first used on the Model 67 in January 1967. Virtual memory support was added to MTS in October 1967. Multi-processor support for a duplex S/360-67 was added in October 1968.
CP/CMS CP/CMS (Control Program/Cambridge Monitor System) is a discontinued time-sharing operating system of the late 1960s and early 1970s, known for its excellent performance and advanced features. It had three distinct versions: * CP-40/CMS, an im ...
was the first
virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...
operating system. Developed at IBM's
Cambridge Scientific Center The IBM Cambridge Scientific Center was a company research laboratory established in February 1964 in Cambridge, Massachusetts. Situated at 545 Technology Square (''Tech Square''), in the same building as MIT's Project MAC, it was later renamed ...
(CSC) near MIT. CP/CMS was essentially an unsupported research system, built away from IBM's mainstream product organizations, with active involvement of outside researchers. Over time it evolved into a fully supported IBM operating system (
VM/370 VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules (emulator), Hercules emulator for personal computers. The ...
and today's
z/VM z/VM is the current version in IBM's VM family of virtual machine operating systems. z/VM was first released in October 2000 and remains in active use and development . It is directly based on technology and concepts dating back to the 1960s, wi ...
).
VP/CSS VP/CSS was a time-sharing operating system developed by National CSS. It began life in 1968 as a copy of IBM's CP/CMS, which at the time was distributed to IBM customers at no charge, in source code form, without support, as part of the IBM Ty ...
, based upon CP/CMS, was developed by
National CSS National CSS, Inc. (NCSS) was a time-sharing firm in the 1960–80s, until its acquisition by Dun & Bradstreet in 1979. NCSS was originally headquartered in Norwalk, Connecticut, but relocated to Wilton in 1978. Sales offices, data centers, and ...
to provide commercial time-sharing services.


Legacy

The S/360-67 had an important legacy. After the failure of
TSS/360 The IBM Time Sharing System TSS/360 is a discontinued early time-sharing operating system designed exclusively for a special model of the System/360 line of mainframes, the Model 67. Made available on a trial basis to a limited set of custom ...
, IBM was surprised by the blossoming of a time-sharing community on the S/360-67 platform (
CP/CMS CP/CMS (Control Program/Cambridge Monitor System) is a discontinued time-sharing operating system of the late 1960s and early 1970s, known for its excellent performance and advanced features. It had three distinct versions: * CP-40/CMS, an im ...
, MTS,
MUSIC Music is generally defined as the art of arranging sound to create some combination of form, harmony, melody, rhythm or otherwise expressive content. Exact definitions of music vary considerably around the world, though it is an aspe ...
). A large number of commercial, academic, and service bureau sites installed the system. By taking advantage of IBM's lukewarm support for time-sharing, and by sharing information and resources (including source code modifications), they built and supported a generation of time-sharing centers. The unique features of the S/360-67 were initially ''not'' carried into IBM's next product series, the
System/370 The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path ...
, although the 370/145 had an associative memory that appeared more useful for paging than for its ostensible purpose. This was largely fallout from a bitter and highly visible political battle within IBM over the merits of
time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence ...
versus
batch processing Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...
. Initially at least, time-sharing lost. However, IBM faced increasing customer demand for time-sharing and virtual memory capabilities. IBM also could not ignore the large number of S/360-67 time-sharing installations – including the new industry of
time-sharing In computing, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence ...
vendors, such as
National CSS National CSS, Inc. (NCSS) was a time-sharing firm in the 1960–80s, until its acquisition by Dun & Bradstreet in 1979. NCSS was originally headquartered in Norwalk, Connecticut, but relocated to Wilton in 1978. Sales offices, data centers, and ...
and
Interactive Data Corporation ICE Data Services (formerly known as Interactive Data) was an American 1960s-founded Time-sharing services company that later became known for providing financial market data (financial data vendor), analytics and related solutions to financial ...
(IDC), that were quickly achieving commercial success. In 1972, IBM added virtual memory features to the S/370 series, a move seen by many as a vindication of work done on the S/360-67 project; the microcode in the 370/145 was updated to use the associative memory for virtual address translation. The survival and success of IBM's VM family, and of virtualization technology in general, also owe much to the S/360-67. In 2010, in the technical description of its latest mainframe, the z196, IBM stated that its software virtualization started with the System/360 model 67.


See also

*
Virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...


References

* E.W. Pugh, L.R. Johnson, and John H. Palmer, ''IBM's 360 and early 370 systems,'' MIT Press, Cambridge MA and London, , includes extensive (819 ''pp.'') treatment of IBM's offerings during this period * Melinda Varian
''VM and the VM community, past present, and future''
SHARE 89 Sessions 9059-9061, 1997 ;S360 : ;func67 :


External links

* A. Padegs
"System/360 and Beyond"
''IBM Journal of Research & Development, vol. 25 no. 5, pp.'' 377-390, September 1981
''IBM System/360 System Summary''
thirteenth edition, January 1974, IBM publication GA22-6810-12, pages 6–13 to 6-15 describe the model 67
IBM System/360 Model 67 Reference Data (Blue card)


of a dual processor IBM 360/67 at the
University of Michigan , mottoeng = "Arts, Knowledge, Truth" , former_names = Catholepistemiad, or University of Michigania (1817–1821) , budget = $10.3 billion (2021) , endowment = $17 billion (2021)As o ...
's academic Computing Center in the late 1960s or early 1970s are included in Dave Mills' article describing the
Michigan Terminal System The Michigan Terminal System (MTS) is one of the first time-sharing computer operating systems.. Developed in 1967 at the University of Michigan for use on IBM S/360-67, S/370 and compatible mainframe computers, it was developed and used by a con ...
(MTS)
Pictures of an IBM S/360-67 at Newcastle (UK) University

TSS/360 Concepts and Facilities

Time-sharing in the IBM System/360 model 67
{{DEFAULTSORT:IBM System 360 Model 67 System 360 Model 67 Computing platforms Time-sharing Computer-related introductions in 1968 VM (operating system)