Browse Prior Art Database

I/O Channel for Computer

IP.com Disclosure Number: IPCOM000075193D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Palm, RA: AUTHOR [+3]

Abstract

The CPU (central processing unit) 10 transmits and receives data in words of 16 bits, and the I/O devices 20 and 24 receive and transmit data in 8-bit bytes. The I/O channel 15, in an output operation, stores the 16-bit words from the CPU 10 and transmits the data in 8-bit bytes to the I/O devices 20 and 24. Conversely, in an input operation, data is received from the I/O devices 20 and 24 by the channel 15 in 8-bit bytes and is transmitted back to the CPU 10 in 16-bit words.

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I/O Channel for Computer

The CPU (central processing unit) 10 transmits and receives data in words of 16 bits, and the I/O devices 20 and 24 receive and transmit data in 8-bit bytes. The I/O channel 15, in an output operation, stores the 16-bit words from the CPU 10 and transmits the data in 8-bit bytes to the I/O devices 20 and 24. Conversely, in an input operation, data is received from the I/O devices 20 and 24 by the channel 15 in 8-bit bytes and is transmitted back to the CPU 10 in 16-bit words.

The storage access channel 12 transmits data to and from the CPU 10 in 16- bit words, and the SAC control 14 interfaces the CPU with the I/O channel 15. The I/O devices 20 and 24 are standard IBM System 360 or 370 interface I/O devices, such as a reader or a punch; and the bus 18 transmits data in 8-bit bytes to or from I/O devices 20 and 24.

Storage 26 stores all data that is either transferred to or from the CPU 10 and to or from the I/O device 20. The "A" buffer 28 acts as a preliminary storage for 8 bits of a 16-bit word that comes from the CPU 10 and is eventually stored in data storage 26, and also acts to store 8 bits from I/O device 20 and interface 16 that eventually are stored in storage 26. The "B" buffer 30 stores the other 8 bits of a 16-bit word from the CPV 10 prior to the 8 bits being stored in storage 26. The "B" buffer 30 also stores commands for I/O device 20.

The CCW (channel control word) address register 32 stores the address of the next sequent...