| 词条 | IBM 2501 | |||||||||||||||
| 释义 |
The IBM 2501 is a punched-card reader from IBM with models for the System/360 and System/370 mainframe systems and for the IBM System/360 Model 20, the IBM 1130 and IBM System/3 minicomputers. 2501 models can read 80-column cards at either 600 or 1000 cards per minute (CPM).[1] The 2501 is no longer sold, but is supported by software of current IBM systems.[2] ModelsThe 2501 comes in four models depending of speed and attachment features. Models for mainframe use come with an integrated control unit that performs the functions of a control unit required by other devices. The A1 and A2 are for the IBM 1130.[3]
UsageThe 2501 uses a photoelectric sensor to read the data punched in the card. Cards are read serially (column by column) and the reader uses a simplified "straight through" card path. "Each column is read twice and the two readings are compared to check reading accuracy."[4] In a mainframe environment the 2501 was frequently used for mainframe input in an "open shop" environment where users submitted their own jobs.[5][6] On an 1130 system the 2501 can be used in addition to the IBM 1442 Since the 1442 has a maximum speed of 300 or 400 CPM attaching a 2501 provides a significant increase in read speed and lower CPU usage. The System/3 normally processes 96-column punched cards, the 2501 provides alternative input for shops that require the ability to read 80-column cards. FeaturesA special feature (RPQ) is available for all models to allow them to read optically-marked (OMR) cards.[7] See also
References1. ^{{cite book|last1=IBM Corporation|title=IBM Field Engineering Theory of Operation: 2501 Card Reader Model A|date=1967|url=http://bitsavers.trailing-edge.com/pdf/ibm/25xx/Y31-0069_2501_Card_Reader_FETOM_Feb67.pdf|accessdate=July 29, 2016}} 2. ^{{cite web|last1=IBM Corporation|title=Identifying I/O device requirements|url=https://www.ibm.com/support/knowledgecenter/SSLTBW_1.13.0/com.ibm.zos.r13.e0zb100/devsupt.htm|website=IBM Knowledge Center|accessdate=July 29, 2016}} 3. ^IBM 1130 Functional Characteristics manual, p. 3 4. ^{{cite web|last1=Shubs|first1=Howard|title=Punched Card Input/Output Devices|url=http://www.ibm1130.net/functional/Cards.html|website=IBM1130.net|accessdate=July 29, 2016}} 5. ^{{cite web|last1=Da Cruz|first1=Frank|title=The IBM 2501 Card Reader|url=http://www.columbia.edu/cu/computinghistory/2501.html|website=Columbia University Computing History|publisher=Columbia University|accessdate=July 29, 2016}} 6. ^{{cite book|last1=University of Michigan|title=Introduction to the Computing Center|date=September 1980|page=93|url=https://books.google.com/books?id=qJ0mP7wJ8xYC|accessdate=July 29, 2016}} 7. ^{{cite book|last1=IBM Corporation|title=IBM 1130 Computing System, IBM[ System/360 Models 25, 30, 40, 44, 50, 65, and IBM System/360 Model 20-Special Feature Description Optical Mark Reading for IBM 2501 Card Reader and IBM 2560 Multi-Function Card Machine|date=November 1969|url=http://bitsavers.trailing-edge.com/pdf/ibm/25xx/GA15-8002-0_2501_2560_Mark_Sense_RPQ_Nov69.pdf|accessdate=July 29, 2016}} 4 : Computer peripherals|IBM mainframe computers|Punched card|Card reader (punched cards) |
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