IBM 370

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IBM 370

This article is provided by FOLDOC - Free Online Dictionary of Computing (


The IBM mainframe line that superseded System/360. Introduced in 1970, the System/370 added virtual memory and other enhancements. In the early 1980s, IBM added Extended Architecture (XA) to the series, featuring I/O enhancements and increased addressing from 24 to 31 bits. In the late 1980s, it debuted the Enterprise System Architecture (ESA), which added more registers and address modes.

The 370 architecture was brought down to the PC level in 1983 with the PC XT/370, and then again in 1989 with the VM/SP Technical Workstation. See System/360, System/390 and IBM mainframes.

As impressive as this Model 155 was, there is more computational power in any modern personal computer. Nevertheless, machines of this type routinely processed millions of records for the world's largest companies. They were doing real "data processing," not graphics processing for the user interface, which swallows up most of a computer's machine cycles these days. (Image courtesy of IBM.)
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For example, the IBM 370 model 158 computed at 1 MIP, had 87 MB of disk capacity--or about 2 percent of a cell-phone's computing power and storage.
Timeline of Events YEAR SABR & Baseball Events IT Events 1971 SABR Founded IBM 370 Intel 4004 8-inch floppy 1974 BRA (Palmer/Cramer) Altair MITS PC 1976 Wiley BRJ article Microsoft founded Ethernet deployed at Xerox PARC 1977 First Baseball Abstract 1978 Intel 8086 introduced 1979 Runs Created created by Bill James Dr.
Already attuned to the building digital tsunami of the time, she turned in her dissertation on green and white paper printed from her IBM 370. "I was the first in the program to use a word processor rather than a typewriter.
At the heart of the system were two IBM 370 computers, model 148, with massive storage capacities.
Preference operates on IBM 370 and compatible mainframes under MVS/SP, MVS/XA, VM/SP and VM/XA, and it can also run in a stand-alone VM environment.
The CSI-X.25 multi-protocol controller (Microtronix Systems Ltd.) connects X.25 public and private networks to IBM 370 host computers, as well as asynchronous terminals and IBM SNA/SDLC controllers [7].
For comparison, we note that both the Vax and the IBM 370 have 16 GPRs.
This is similar to the IBM 370 design, in which there are four FP registers.
The CLIPPER microprocessor has a load/store architecture; i.e., most of the references to memory are via load and store instructions in contrast to both the IBM 370 and DEC Vax which make extensive use of their register/memory operations (370 RX type instructions) and memory-to-memory (370 SS type) instructions.
The long 32-bit displacement eliminates the aggravating addressability problem posed by the 12-bit displacement of the IBM 370. The register + 12-bit displacement mode saves 4 bytes, if only a short displacement is needed, and the relative (register with no displacement) mode requires two bytes less.
In the process, he made the transition from circuit design to software "very reluctantly." He first worked on the IBM 370's engineering design.
Instead, he started at IBM in 1965 as a staff engineer working on the design for the IBM 370. He contributed to the multiprocessor and fault-tolerant hardware architecture and the address translation hardware that was required to implement virtual storage.