provides an information format and control signal
sequences that are independent of the type of con
trol unit and channel and provide a uniform means
of attaching and controlling various types ofI/O devices. I/O devices that do not use the I/O interface
employthe same information format and control
signal sequences. Devices and Control Units
Input/ output devices include such equipment as card
readers and punches, magnetic tape units, disk stor
age, drum storage, typewriter-keyboard devices,
printers, teleprocessing devices, and sensor-based
equipment.
ManyI/O devices function with an external doc
ument, such as a punched card or a reel of magnetic
tape.Some I/O devices handle only electrical sig
nals, such as those found in sensor-based networks.
In either case,I/O device operation is regulated by a
control unit. The control-unit function may be
housed with theI/O device or in the CPU, or a sep-
18 System/370 Principles of Operation
arate control unit may be used. In all cases, the
control-unit function provides the logical and buffer
ing capabilities necessary to operate the associatedI/O device. From the programming point of view,
most control-unit functions merge withI/O device
functions.
System Console
The system console provides the functions necessary
to operate and control the system. It consists of a
system control panel and, in most cases, an associat
ed console device, which may also be used as anI/O device for communicating with the supervisory pro
gram and problem programs. The need for operator
manipulation of manual controls is held to a mini
mum by the system design and the governing super
visory program.
The main functions provided by the system con
sole include power-on/ off, reset, initial-pro gram
loading, start/stop, and display and enter functions.
sequences that are independent of the type of con
trol unit and channel and provide a uniform means
of attaching and controlling various types of
employ
signal sequences.
Input/ output devices include such equipment as card
readers and punches, magnetic tape units, disk stor
age, drum storage, typewriter-keyboard devices,
printers, teleprocessing devices, and sensor-based
equipment.
Many
ument, such as a punched card or a reel of magnetic
tape.
nals, such as those found in sensor-based networks.
In either case,
control unit. The control-unit function may be
housed with the
18 System/370 Principles of Operation
arate control unit may be used. In all cases, the
control-unit function provides the logical and buffer
ing capabilities necessary to operate the associated
most control-unit functions merge with
functions.
System Console
The system console provides the functions necessary
to operate and control the system. It consists of a
system control panel and, in most cases, an associat
ed console device, which may also be used as an
gram and problem programs. The need for operator
manipulation of manual controls is held to a mini
mum by the system design and the governing super
visory program.
The main functions provided by the system con
sole include power-on/ off, reset, initial-pro gram
loading, start/stop, and display and enter functions.