main page pool:
In
DOSIVS, the set of
all
page frames
in
real
storage not assigned
to
the supervisor or one
of
the
real
partitions.
main storage:
1. The
real
address area of virtual storage. Contrast with auxiliary
storage.
2.
All
program addressable storage from which instructions may be executed
and from which data can
be
loaded directly into registers.
master
scheduler: The part
of
the control program
that
responds
to
operator
commands and returns required information.
MCAR
Maintenance Control Address Register
(Mod 165 and 168)
MCDR
Maintenance Control Data Register
(Mod
165 and 168)
MCER
Maintenance Control Entry Register
(Mod 165 and 168)
microprogram: A set
of
basic
or
elementary machine instructions
that
is
loaded into
control storage
to
control
CPU
operations.
module (programming): A program unit that
is
input to,
or
output
from, a single
execution of an assembler, compiler, or linkage editor; a source, object,
or
load
module.
move mode: A way of providing data by moving it instead
of
pointing
to
its location.
MRAR
Maintenance Ripple Address Register
(Mod 165 and 168)
multijob operation: Concurrent execution of job steps from two or more jobs.
multiplexer channel: A channel designed to operate with a number
of
I/O
devices
simultaneously on a byte basis. That
is,
several
I/O
devices can
be
transferring records
over the
multiplexer channel, time-sharing it on a byte basis.
multiplexer mode: A means of transferring records to or from low·speed
I/O
devices
on the
multiplexer channel, by interleaving bytes
of
data. The multiplexer channel
sustains simultaneous I/O operations on several subchannels. Bytes
of
data are inter·
leaved
and then routed
to
or
from the selected
I/O
devices
or
to
and from the desired
locations
in
main storage. Multiplex mode
is
sometimes referred
to
as
byte mode.
multiprogramming system: A system
that
controls more than one program simulta·
neously by interleaving their execution.
multitasking: The concurrent execution of one main task and one or more subtasks
in
the same position.
n
name: A set of one
to
eight characters
that
identifies a statement, data set, module,
etc., and
that
is
usually associated with the location of that which it identifies.
nucleus: That part of the
control program that must always
be
present
in
main
storage.
Also, the main storage area used by the nucleus and other transient control
program routines.
o
object module: The
output
of
a single execution of
an
assembler
or
compiler, which
constitutes input
to
linkage editor.
An
object module consists of one
or
more control
sections
in
relocatable, though not executable, form and an associated control dictio-
nary.
offline:
1.
• Pertaining
to
equipment or devices not under control
of
the central
processing unit.
2.
Pertaining
to
program error diagnosis without using the computer
system
(offline program debugging).
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