The P/370 Environment

Content by McGill Systems Inc. (original archived HERE) Last update: 29 Oct 1995

Personal Computing and the 370 Instruction Set

The personal computer (PC) was originally introduced to provide a single user computer resource on the desktop. Since its introduction, its speed has increased and its hardware cost has dropped dramatically.

It is now at the point that it makes sense to run multiple users concurrently on a single PC.

The software to support multiple users on a single computer has reached a highly developed state on the mainframe platform. Such systems as MUSIC/SP, VM and VSE have been in use for years providing such support.

These systems use preemptive multi-tasking, virtual storage, 32 bit instruction sets and storage protection to enable the efficient use of a shared computer.

The IBM System/370 instruction set is used by these systems to perform its tasks.

Over the years many applications have been developed for this environment and they too use the 370 instruction set. This 370 instruction set is not supported by the standard processors that run on personal computers. However, a P/370 card can be added to the personal computer to give it this capability.

This addition gives you a second powerful processor and additional 16 MB of storage on your personal computer.

Personal/370 Option

The IBM Personal/370 (P/370) is an option card that can be added to a PS/2 personal computer to enable the running operating systems such as MUSIC/SP, VM and VSE at the same time as running personal computer software running under OS/2, DOS and Windows.

This same card can be added to an IBM RS/6000 computer to enable the running operating systems such as MUSIC/SP, VM, and VSE at the same time as running operating systems such as IBM's AIX system.

The P/370 is a complete implementation of the IBM S/370 Processor including a floating point co-processor on a single adapter card. It supports 4K page frames used by MUSIC/SP, VM, MVS, and VSE. It also contains 16 million bytes of storage to be used by programs using the 370 instructions. This is in addition to the storage that is used by applications running under the PS/2 or RS/6000 processor.

This P/370 card enables the personal computer to support applications that would normally only run in a host computing environment such as on an ES/9000 mainframe. In addition it allows multiple concurrent users to run simultaneously on the computer. These users can be connected to the personal computer via dial-in, local area network or world-wide connections to networks such as the Internet.

370 Channel Option

The IBM 370 Channel card is another card that can be added to provide direct connectivity of many I/O devices that would normally only connect to a mainframe channel. Examples include tape drives such as the IBM 3400 and 3480 series, IBM 3270 local control units such as the IBM 3x74 and the IBM 7171 protocol converter. These devices are connected to this adapter card using the standard bus and tag cables used to connect the control units to mainframe systems.

This channel card will not support mainframe disks devices. This is not a problem as normally you would want to use the hard disk drives available on a personal computer platform instead of these devices.

This channel adapter features a built-in 64K buffer.

Benefits of Running a P/370 Environment

Key benefits of running in a P/370 environment on an IBM PS/2 are:

  • Takes advantage of the lower cost of personal computer hardware such as the costs of RAM and disk storage.
  • Supports many users on a hardware configuration that does not require special computer room temperature controls or special power requirements.
  • Can use a small uninterruptible power supply (UPS) to protect from the effects of power outages, power glitches, etc. This can be done at a small fraction of the costs of a UPS for a mainframe computer.
  • Can distribute the computing power closer to the users to reduce communications costs.
  • Can run systems such as MUSIC/SP, VM, VSE and the applications that run under them that would normally require mainframe configurations. This makes it an ideal platform for "right-sizing" without the headaches of conversion that would normally be involved in porting to other architectures.
  • Can use personal computer backup programs and hardware devices to backup the information on the disks. Can attach many mainframe I/O devices to the PC platform with the addition of the 370 channel card.
  • Can work with RAID disk technology to provide data redundancy and reliability. This enables your system to continue to operate if a single disk drive fails and allows a replacement to be installed without a system outage.
  • Runs in an IBM PS/2 configuration that IBM includes 3-year on-site warranty service included in the purchase price.
  • The single hardware configuration supports most of the commonly used PC and mainframe software, and can run them concurrently. This includes OS/2, DOS, and Microsoft Windows applications as well as many mainframe applications and systems.

P/370 Card Availability

The IBM P/370 card is available through IBM's OEM channel only. This means that sites cannot directly purchase the card from IBM. There are several companies that will supply the card as part of an application solution. For example, McGill Systems offers the card as part of a MUSIC/SP package.

Here is a list of some of the companies that offer packaged solutions using the P/370 card.

Content created and/or collected by:
Louis F. Ohland, Peter H. Wendt, David L. Beem, William R. Walsh, Tatsuo Sunagawa, Tomáš Slavotínek, Jim Shorney, Tim N. Clarke, Kevin Bowling, and many others.

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