IBM 1130 User Manual page 466

INTRODUC TION
Remember, effective management can make or break
a good installation. ,This also applies to the disk
portion of your 1130. Because the disk is such an
integral part of your system, it is extremely im-
portant that you have the knowledge and ability to
manage it effectively. This discussion of the disk,
its layout, and how the Monitor helps you use it,
will give you a good start toward effective disk
management.
Effective use of your disk cartridges requires a
certain amount of planning, especially if the number
of applications on your 1130 is high, or is expected
to grow. Some control must be exercised over what
gets stored on a disk, and which disk cartridge is to
be used for a particular job.
Each installation requires a certain minimum
number of disk cartridges:
• At least one general purpose systems car-
tridge, with a complete Monitor system (FORTRAN
and Assembler). It should only be used for testing,
one-time applications, and other odd jobs.
• On multiple disk drive systems, at least one
working or scratch disk for each disk drive over
and above the first.
• One disk cartridge to be used for ordering and
receiving programs from IBM. Some packages are
not available in card form and can be obtained only
by forwarding a cartridge to the Program Informa-
tion Department. PID will place the package on
your cartridge and return it to you.
• One disk cartridge (as required) for each of
the major IBM applications programs to be used.
For example, STRESS, COGO, LP-MOSS, and
others each require all or most of a disk cartridge.
• One disk cartridge for each major application
area, such as payroll, accounts payable, plant
scheduling, highway design, etc. In some cases,
two applications must share a disk because they
both use the same data file, but such dual use
should be avoided whenever possible.
Mixing of different applications on the same disk
may lead to several complications, especially if
different programmers are involved. For example:
1.
Duplicate program and data file names may
occur, with resulting confusion.
2. One program may inadvertently write into the
disk data area of another program.
3. The amount of Working Storage is decreased
more rapidly as each application area adds pro-
grams, subprograms, etc.
Section Subsections
Page
60 01
I
00 01
4. Run times may increase as data files are
pushed further apart by the continuous storing and
deleting of programs, data files, etc.
5. Overall control is diminished.
Before discussing disk storage management,
several terms must be defined:
Systems cartridge -- a cartridge that contains
the 1130 Disk Monitor system. If your 1130 has
only one disk drive, all your cartridges must be
systems cartridges.
Non-systems cartridge -- a cartridge that does
not contain the monitor system. As implied
above, such a cartridge would be of use only in
installations with two or more disk drives.
Master cartridge -- a systems cartridge that has
been referenced by the cold start procedure, or
by a Job card. The Monitor system on that car-
tridge will be the one in use until another cold
start is initiated, or until a Job card is encoun-
tered that switches control to a different car-
tridge. Obviously, on a one-drive 1130 system,
the one and only disk cartridge will be both a
systems disk and the master disk.
Satellite cartridge -- any cartridge which is not
the master cartridge. It may be either a systems
or non-systems cartridge.
You see, then, that there is a definite distinction
between these terms. A disk cartridge is either a
systems or non-systems disk, depending on whether
you have loaded the Monitor system onto it. On the
other hand, the master/satellite split does not
occur until the cartridges are placed in the drives,
made ready, and a cold start performed. Then, one
becomes the master, and the others, if any, become
satellites.
The terminology of the disk drives themselves
involves another distinction -- that of physical
drives versus logical drives. Single-drive 1130
users need not concern themselves with this; their
one disk drive is physical drive 0 and logical drive
o --
there are no options. - - - - -
• Each disk drive on the 1130 has a physical
drive number; drive 0 is the one contained in the
mainframe of the 1130; drives 1 through 4 are con-
tained in the 2310 enclosure, a separate unit. These
numbers are fixed and cannot be changed.
• Each disk drive present on the 1130 may also
be given a logical drive number, which mayor may
not agree with its physical number. The only