Editing IBM System/3 (section)

==Hardware==
[[File:System 3 punch card.jpg|thumb|96-column punched card]]
[[File:Interfaccia di acquisizione dati di IBM sistema 3 - Museo scienza tecnologia Milano D0832.jpg|thumb|IBM 5496 Data Recorder, the keypunch for 96-character cards]]
[[File:Selezionatrice di IBM sistema 3 - Museo scienza tecnologia Milano D0833.jpg|thumb|IBM 5486 Card Sorter used with System/3 punched cards]]
The IBM System/3 was announced as a computer system that initially consisted of:
<ref>[http://ed-thelen.org/comp-hist/IBM-ProdAnn/syst3.pdf IBM Field Engineering Announcement: IBM System/3]</ref>
* IBM 5410 Model 10 Central Processing Unit
* IBM 5424 Multi Functional Card Unit (MFCU)
* [[IBM hammer printers#IBM 5203|IBM 5203 Line Printer]]
* IBM 5444 Disk Storage (optional)
* IBM 5471 Printer Keyboard
* IBM 5475 Data Entry Keyboard
* IBM 5496 Data Recorder, a keypunch machine with print and verify functions
* IBM 5486 Card Sorter

===Memory===
Entry models had as little as 4K (4096) bytes of [[magnetic-core memory]].

===Direct access storage===
{{See also|IBM 5444}}
For mass storage, the System/3 used the [[IBM 5444]] single-platter [[hard disk|disk]],<ref>[http://ed-thelen.org/comp-hist/IBM-ProdAnn/syst3.pdf System/3], IBM engineering announcement</ref> roughly the size of a large pizza; initially each platter held 2.5 MB of data. Standard configuration for storage was one or two fixed disks, each in a separate pull-out drawer, which typically held the operating system and user-developed programs. Additionally, each fixed disc could have a removable cartridge disk attached; these typically contained the data-files associated with various applications, for example Payroll, and users frequently had a number of them. Thus the low-end systems could support a maximum of 10 MB of online storage (two fixed, two removable), although in practice this was very expensive and not common.

The System/3 was also available with the IBM 5445 disk drive (20mb) and later the model 15 allowed "winchester" style 3340 drives. On the smaller models, while you could attach 5445 drives, you had to keep the 5444 for the operating system and other programming libraries, however that limitation was changed with software called elimn8 which allowed 5445 drives to totally replace the 5444's. Other companies such as Memorex manufactured compatible 5445 drives for the System/3.

===Multi-Function Card Unit===
The most common punched-card device was IBM 5424 Multifunction Card Unit (MFCU) which read, punched, printed on and sorted the new, smaller 96-column [[punched card]]s. Instead of the rectangular punches in the classic 80-column IBM card, the new cards had tiny (1&nbsp;mm), circular holes much like [[paper tape]]. Data was stored in six-bit [[binary-coded decimal]] code, with three rows of 32 characters each, or in 8-bit [[EBCDIC]], with the two extra holes located in the top rows.
The new cards had room for 128 printed characters in four rows of 32 characters each. They were about 1/3 the size of the older 80 column cards but held 20% more text data. The smaller, and thus lighter card could be processed with faster equipment and with fewer jams.

Available as ''RPQ''s (special order equipment) to handle 80-column cards were the IBM 2560 Multifunction Card Machine (MFCM) which could read, punch, interpret and sort, and the [[IBM 1442]] which could only read and punch.

===Magnetic tape===
Offline storage was available with the purchase of an external tape drive which read and wrote standard IBM [[9-track tape]].

The System/3 Mod 10 optionally included the IBM 3410 magnetic tape subsystem.

===Operator Console Facility===
The System/3 Operator Console Facility (OCF) consisted of either a modified [[IBM Selectric typewriter]] interfaced into the computer, or a special purpose [[IBM 3270]] display.
Within the OCF, there was capability to 'cancel' processes and/or tasks that were running, including either partition (P1 or P2). The system could only run two programs simultaneously, except for the model 15 or systems running the Communications Control program, CCP. The CCP was a system control programming feature that allowed to support an online network of [[Computer terminal|terminal]]s.

===Printers===
[[File:Stampante di IBM sistema 3 - Museo scienza tecnologia Milano D0831.jpg|thumb|IBM 5203 printer for System/3]]
A smaller (IBM 5203) printer was attached to the main system. The 5203 was a chain printer with interchangeable cartridges.  It could run at 100 or 200 lines per minute, based on model.<ref>{{Cite book|last=Pugh|first=Emerson|title=IBM's 360 and Early 370 Systems|publisher=MIT Press|year=1991|pages=449}}</ref> Later on, IBM offered multiple models of the existing [[IBM 1403]] printer line, which had been originally built for the [[IBM 1401]] computer.

===Floppy disk===
With the arrival of the [[IBM 3740]] data entry system, the System/3 Model 10 got a feature called LCA (local communication adaptor) which allowed an IBM 3741 station to be "attached" to the system to transmit/receive data. Later models of the System/3 such as the Model 8 were cardless and used the [[Floppy disk#8-inch floppy disk|8" 3740 style floppy disk]].