Resources on iSeries Spools

Spools on IBM iSeries

iSeries

The Application System/400 (also known as AS/400), now System i (also known as iSeries), is a type of minicomputer produced by IBM. It was first produced in 1988. It was then renamed to the eServer iSeries in 2000 as part of IBM's e-Server branding initiative. Now with the global move of the server and storage brands to the System brand with the Systems Agenda, the family has been renamed to System i in 2006, with the POWER5-based members of the series being called the System i5.

History
The AS/400 was the result of the combination of the System/38 database machine (announced by IBM in October 1978 and delivered in August 1979) and the System/36. The first AS/400 systems (known by the development code names Silverlake and Olympic) were delivered in 1988, and the product line has been refreshed continually since then. The programmers who worked on OS/400, the operating system of the AS/400, did not have a UNIX background. Dr Frank Soltis, the chief architect, says that this is the main difference between this and any other operating system.

The AS/400 was the first general-purpose computer system to attain a C2 security rating from the NSA, and in 1995 was extended to employ a 64-bit processor and operating system.

In 2000 IBM renamed the AS/400 to iSeries, as part of its e-Server branding initiative. The product line was further extended in 2004 with the introduction of the i5 servers, the first to use the IBM POWER5 processor. The architecture of the system allows for future implementation of 128-bit processors when they become available. Existing programs will use the new hardware without modification.

Although announced in 1988, the AS/400 remains IBM's most recent major architectural shift that was developed wholly internally. Since the arrival of Lou Gerstner in 1993, IBM has viewed such colossal internal developments as too risky. Instead, IBM now prefers to make key product strides through acquisition -- e.g. the takeovers of Lotus Software and Rational Software -- and to support the development of open standards, particularly Linux. It is noteworthy that after the departure of CEO John Akers in 1993, when IBM looked likely to be split up, Bill Gates commented that the only part of IBM that Microsoft would be interested in was the AS/400 division. (At the time, many of Microsoft's internal systems ran on the AS/400 platform.)

Excerpt from "IBM System i." Wikipedia, The Free Encyclopedia. 27 Oct 2006, 13:34 UTC. Wikimedia Foundation, Inc. 27 Oct 2006 http://en.wikipedia.org/w/index.php?title=IBM_System_i&oldid=84043862

Image from Ian Jarman, The Future Simplified. IBM eServer iSeries. 14. Apr 2005, 16:21 UTC.

Spools

In computer science, spooling refers to putting jobs in a buffer, a special area in memory, or on a disk where a device can access them when it is ready. This is similar to a sewing machine spool, which a person puts thread onto, and a machine pulls at its convenience. Spooling is useful because devices access data at different rates. The buffer provides a waiting station where data can reside while the slower device catches up. Material is only added and deleted at the ends of the area; there is no random access or editing. This also allows the CPU to work on other tasks while waiting for the slower device to do its task.

It can also refer to a storage device that incorporates a physical spool, such as a tape drive.

The most common spooling application is print spooling. In print spooling, documents are loaded into a buffer (usually an area on a disk), and then the printer pulls them off the buffer at its own rate. Because the documents are in a buffer where they can be accessed by the printer, the user is free to perform other operations on the computer while the printing takes place in the background. Spooling also lets users place a number of print jobs in a queue instead of waiting for each one to finish before specifying the next one.

The temporary storage area to which e-mail is delivered by a Mail Transfer Agent and in which it waits to be picked up by a Mail User Agent is sometimes called a mail spool. Likewise, a storage area for Usenet articles may be referred to as a news spool. (On Unix-like systems, these areas are usually located in the /var/spool directory.) Unlike other spools, mail and news spools usually allow random access to individual messages.

Excerpt from "Spooling." Wikipedia, The Free Encyclopedia. 3 Sep 2006, 08:51 UTC. Wikimedia Foundation, Inc. 27 Oct 2006 http://en.wikipedia.org/w/index.php?title=Spooling&oldid=73544951