Editing IBM System/360 (section)

==Peripherals==
IBM developed a new family of peripheral equipment for System/360, carrying over a few from its older 1400 series. Interfaces were standardized, allowing greater flexibility to mix and match processors, controllers and peripherals than in the earlier product lines.

In addition, System/360 computers could use certain peripherals that were originally developed for earlier computers. These earlier peripherals used a different numbering system, such as the [[IBM 1403]] chain printer. The 1403, an extremely reliable device that had already earned a reputation as a workhorse, was sold as the 1403-N1 when adapted for the System/360.

Also available were [[optical character recognition]] (OCR) readers IBM 1287 and IBM 1288 which could read Alpha Numeric (A/N) and Numeric Hand Printed (NHP/NHW) Characters from Cashier's rolls of tape to full legal size pages. At the time this was done with very large optical/logic readers. Software was too slow and expensive at that time.

Models 65 and below sold with an IBM 1052–7 as the console typewriter. The 360/85 with feature 5450 uses a display console that was not compatible with anything else in the line;<ref>{{cite book |publisher=IBM Corporation |title=IBM System/360 Operating System Operator's Guide for Display Consoles |date=1972 |page=9 |url=http://www.bitsavers.org/pdf/ibm/360/os/R21.0_Mar72/CG27-6949-1_Operators_Guide_For_Display_Consoles_Rel21_Mar72.pdf |access-date=July 13, 2020}}</ref><ref>{{cite book
 |     title = IBM System/360 Operating System MVT Supervisor 
 |        id = GY28-6659-7
 |      date = May 1973
 |   edition = Eighth
 |    series = Program Logic
 |       url = http://bitsavers.org/pdf/ibm/360/os/R21.7_Apr73/plm/GY28-6659-7_MVT_Supervisor_PLM_Rel_21.7_May73.pdf
 | publisher = [[IBM]]
 }}
</ref> the later 3066 console for the 370/165 and 370/168 use the same basic display design as the 360/85.
The IBM System/360 models 91 and 195 use a graphical display similar to the IBM 2250 as their primary console.

Additional operator consoles were also available.  Certain high-end machines could optionally be purchased with a [[IBM 2250|2250]] graphical display, costing upwards of US$100,000; smaller machines could use the less expensive [[IBM 2260|2260]] display or later the [[IBM 3270|3270]].

===Direct access storage devices (DASD)===
{{Further|Direct-access storage device}}[[Image:IBM 2311 memory unit.JPG|thumb|IBM 2311 disk drive]]
{{See also|History of IBM magnetic disk drives#IBM S.2F360 and other IBM mainframe HDDs|l1=IBM S/360 and other IBM mainframe HDDs}}

The first disk drives for System/360 were [[IBM 2302]]s<ref name=GA26-5988/>{{rp|60–65}} and [[IBM 2311]]s.<ref name=GA26-5988/>{{rp|54–58}} The first drum for System/360 was the [[IBM 7320]].<ref name="IBM 7320">{{cite book
 | title      = IBM 7320 Drum Storage
 | id         = G22-6717
 | date       = 1962
 | publisher  = IBM Corporation
 | url        = http://www.bitsavers.org/pdf/ibm/7090/G22-6717_7320_7631_1962.pdf
 | access-date = Dec 6, 2019
 | ref        = IBM 7320
 | mode       = cs2}}</ref><ref name=A26-5988-0>{{cite book
 | title      = IBM System/360 Component descriptions-2841 Storage Control Unit 2302 Disk Storage Models 3 and 4 2311 Disk Storage Drive 2321 Data Cell Drive Model 1 7320 Drum Storage
 | id         = A26-5988-0
 | url        = http://bitsavers.org/pdf/ibm/2841/A26-5988-0_2841_2311_2321_7320_Descr.pdf
 | access-date = Dec 6, 2019
 | ref        = IBM 2841
 | mode       = cs2}}</ref>{{rp|41}}
<!-- I'm getting 404 trying to get to bitsavers - I'd appreciate it if someone could add the information for the 2301 and 2303 manuals. -->

The 156&nbsp;kbit/s 2302 was based on the earlier [[IBM 1302|1302]] and was available as a model 3 with two 112.79&nbsp;MB modules<ref name=GA26-5988/>{{rp|60}} or as a model 4 with four such modules.<ref name=GA26-5988/>{{rp|60}}

The 2311, with a removable [[IBM 1316|1316]] [[disk pack]], was based on the [[IBM 1311]] and had a theoretical capacity of 7.2&nbsp;MB, although actual capacity varied with record design.<ref name=A26-5988-0/>{{rp|31}} (When used with a 360/20, the 1316 pack was formatted into fixed-length 270 byte [[disk sector|sectors]], giving a maximum capacity of 5.4MB.)
 
In 1966, the first [[IBM 2314|2314s]] shipped. This device had up to eight usable disk drives with an integral control unit; there were nine drives, but one was reserved as a spare. Each drive used a removable [[IBM 2316|2316]] disk pack with a capacity of nearly 28&nbsp;MB. The disk packs for the 2311 and 2314 were ''physically'' large by today's standards — e.g., the [[IBM 1316|1316]] disk pack was about {{convert|14|in|cm|abbr=on}} in diameter and had six platters stacked on a central spindle. The top and bottom outside platters did not store data. Data were recorded on the inner sides of the top and bottom platters and both sides of the inner platters, providing 10 recording surfaces. The 10 read/write heads moved together across the surfaces of the platters, which were formatted with 203 concentric tracks. To reduce the amount of head movement (seeking), data was written in a virtual cylinder from inside top platter down to inside bottom platter. These disks were not usually formatted with fixed-sized sectors as are today's hard drives (though this ''was'' done with [[CP/CMS]]). Rather, most System/360 I/O software could customize the length of the data record (variable-length records), as was the case with magnetic tapes.

[[File:IBM 2314 DiskDrives and IBM 2540 CardReader Punch.jpg|thumb|IBM 2314 disk drives and IBM 2540 card reader/punch at the University of Michigan]]

{{Anchor|IBM2301}}Some of the most powerful early System/360s used high-speed head-per-track drum storage devices. The 3,500&nbsp;RPM 2301,<ref>[http://www.columbia.edu/acis/history/drum.html IBM 2301 Drum Storage], Columbia University Computing History</ref> which replaced the 7320, was part of the original System/360 announcement, with a capacity of 4&nbsp;MB. The 303.8&nbsp;kbit/s [[IBM 2303]]<ref name=GA26-5988>{{cite book | publisher = IBM | title = IBM System/360 Component Descriptions – 2841 and Associated DASD | id = GA26-5988-7 | date = December 1969 | version = Eighth Edition | url = http://bitsavers.org/pdf/ibm/28xx/2841/GA26-5988-7_2841_DASD_Component_Descr_Dec69.pdf | access-date = 2012-01-02 | archive-url = https://web.archive.org/web/20111014155354/http://www.bitsavers.org/pdf/ibm/28xx/2841/GA26-5988-7_2841_DASD_Component_Descr_Dec69.pdf | archive-date = 2011-10-14 | url-status = dead}}</ref>{{rp|74–76}} was announced on January 31, 1966, with a capacity of 3.913&nbsp;MB. These were the only drums announced for System/360 and System/370, and their niche was later filled by fixed-head disks.

The 6,000&nbsp;RPM 2305 appeared in 1970, with capacities of 5&nbsp;MB (2305–1) or 11&nbsp;MB (2305–2) per module.<ref>{{cite web| url = http://ed-thelen.org/comp-hist/IBM-ProdAnn/2305.pdf| title = IBM 2305 product announcement}}</ref><ref>{{cite book | publisher = IBM | title = Reference Manual for IBM 2835 Storage Control and IBM 2305 Fixed Head Storage Module | id = GA26-1689-4 | version = Fifth Edition | date = November 1980}}</ref> Although these devices did not have large capacity, their speed and transfer rates made them attractive for high-performance needs. A typical use was overlay linkage (e.g. for OS and application subroutines) for program sections written to alternate in the same memory regions. Fixed-head disks and drums were particularly effective as paging devices on the early virtual memory systems. The 2305, although often called a "drum" was actually a head-per-track disk device, with 12 recording surfaces and a data transfer rate up to 3&nbsp;MB/s.

Rarely seen was the [[IBM 2321 Data Cell]],<ref>[http://www.columbia.edu/acis/history/datacell.html The IBM 2321 Data Cell Drive], Columbia University Computing History</ref> a mechanically complex device that contained multiple magnetic strips to hold data; strips could be randomly accessed, placed upon a cylinder-shaped drum for read/write operations; then returned to an internal storage cartridge. The IBM Data Cell [noodle picker] was among several IBM trademarked "speedy" mass online direct-access storage peripherals (reincarnated in recent years as "virtual tape" and automated tape librarian peripherals). The 2321 file had a capacity of 400&nbsp;MB, at the time when the 2311 disk drive only had 7.2&nbsp;MB. The IBM Data Cell was proposed to fill cost/capacity/speed gap between magnetic tapes—which had high capacity with relatively low cost per stored byte—and disks, which had higher expense per byte. Some installations also found the electromechanical operation less dependable and opted for less mechanical forms of direct-access storage.

The Model 44 was unique in offering an integrated single-disk drive as a standard feature. This drive used the 2315 "ramkit" cartridge and provided 1,171,200 bytes of storage.<ref name="m44-func-char"/>{{rp|11}}

===Tape drives===
[[File:IBM System 360 tape drives.jpg|thumb|IBM 2401 tape drives]]

The 2400-series of 1/2" magnetic tape units consisted of the 2401 and 2402 Models 1-6 Magnetic Tape Units, the 2403 Models 1-6 Magnetic Tape Unit and Control, the 2404 Models 1-3 Magnetic Tape Unit and Control, and the 2803/2804 Models 1 and 2 Tape Control Units.<ref>{{cite book| url=http://bitsavers.org/pdf/ibm/2400/A22-6862-4_2400_Series_Magnetic_Tape_Units_OEM.pdf |title=IBM 2400-Series Magnetic Tape Units Original Equipment Manufacturers' Information |edition=fifth}}</ref> The later 2415 Magnetic Tape Unit and Control, introduced in 1967 contained two, four, or six tape drives and a control in a single unit, and was slower and cheaper.<ref>{{cite web |url=http://ed-thelen.org/comp-hist/IBM-ProdAnn/2415.pdf |title=IBM 2415 Magnetic Tape Unit and Control for System/360}}</ref> The 2415 drives and control were not marketed separately.<ref>{{cite book |url=http://bitsavers.org/pdf/ibm/2400/GA22-6862-6_2400-Series_OEM_Nov70.pdf |title=IBM 2400-Series Magnetic Tape Units Original Equipment Manufacturers' Information |date=November 1970 |edition=seventh}}</ref> With System/360, IBM switched from [[IBM 7-track]] to [[9-track tape]] format. Some 2400-series drives could be purchased that read and wrote 7-track tapes for compatibility with the older [[IBM 729]] tape drives. In 1968, the IBM 2420 tape system was released, offering much higher data rates, self-threading tape operation and 1600bpi packing density.<ref>{{cite book |url=http://bitsavers.org/pdf/ibm/2420/A32-0004-0_2420_Model_7_OEM_Oct68.pdf |title=IBM 2420 Model 7 Magnetic Tape Unit Original Equipment Manufacturers' Information |date=October 1968}}</ref> It remained in the product line until 1979.<ref>{{cite web |url=https://www.ibm.com/ibm/history/exhibits/storage/storage_2420.html |title=IBM 2420 magnetic tape unit|website=[[IBM]] |date=23 January 2003 }}</ref>

===Unit record devices===
[[Image:IBM line printer 1403.JPG|thumb|[[IBM 1403]] line printer]]

* Punched card devices included the 2501 card reader and the 2540 card reader punch. Virtually every System/360 had a 2540. The 2560 MFCM ("Multi-Function Card Machine") reader/sorter/punch, listed above, was for the Model 20 only. It was notorious for reliability problems (earning humorous acronyms often involving "...Card Muncher" or "Mal-Function Card Machine").
* [[Line printer]]s were the [[IBM 1403]] and the slower [[IBM 1443]].
* A paper tape reader, the IBM 2671, was introduced in 1964. It had a rated speed of 1,000 cps. There were also a paper tape reader and paper tape punch from an earlier era, available only as RPQs ([[Request price quotation|Request Price Quotation]]). The 1054 (reader) and 1055 (punch), which were carried forward (like the 1052 console typewriter) from the IBM 1050 Teleprocessing System. All these devices operated at a maximum of 15.5 characters per second. The paper tape punch from the IBM 1080 System was also available by RPQ, but at a prohibitively expensive price.
* [[Optical character recognition]] (OCR) devices 1287 and later the 1288 were available on the 360's. The 1287 could read handwritten numerals, some OCR fonts, and cash register OCR paper tape reels. The 1288 'page reader' could handle up to legal size OCR font typewritten pages, as well as handwritten numerals. Both of these OCR devices employed a 'flying spot' scanning principle, with the raster scan provided by a large CRT, and the reflected light density changes were picked up by a high gain [[photomultiplier]] tube.
* [[Magnetic ink character recognition]] (MICR) was provided by the IBM 1412 and 1419 cheque sorters, with magnetic ink printing (for cheque books) on 1445 printers (a modified 1443 that used an MICR ribbon). 1412/1419 and 1445 were mainly used by banking institutions.