Table of Contents
Advertisement
and a track extent) for each device to be allocated.
A
sample set of device/area specifications is as follows:
(a)
7204/BO
(b)
SP
=
40
SD
=
20
SL
=--=
20
CP
=
0
FP
=
50
UD
=
100, NO
BT = ALL
(c)
END
Specification (a) defines a Model 7204 RAD unit with de-
vice number BO (on the integral lOP, or IOP1, by default).
Specification
(b)
and those that follow define the areas
desired on that device and the number of tracks to be
assigned to each. The specification "CP
=
0" effectively
deletes the automatic CP entry from the Master Dictionary.
Specification "UD :-:: 100, NO" allocates 100 tracks for the
UD area with no write protection.
Specification IIBT =
ALLII allocates the entire remaining space (ALL) on the
RAD followi ng the F P area (i. e., 262 tracks) to the BT
area.
(Write protection parameters and defaults are de-
scri bed below.)
If the RAD unit on BO were either the last or only device to
be allocated, parameter (c) would be used to end the allo-
cation process.
Note that a" desi red areas other than the system areas SP,
SD,
S~,
BT, and CP must be expli citly allocated. Option-
ally, any or all of these system areas may also be allocated
explicitly, as shown in the above example.
Rule for Use of the Area Parameters. Areas are allocated
in the order specified, and area specifications pertain to the
immediately preceding device definition.
The occurrence of an area spec i fi cati on of the form lIarea=
ALL II causes all of the tracks remaining unallocated at that
point (on the device in question) to be allocated to the de-
fined area. This specification effectively terminates all.o-
cation on that devi
cei
any followi ng are.a or S K specifi cations
for that device will cause an alarm message only.
Rule For Placement of System Bootstrap. Each disk device
allocated during SYSGEN wi
II
automati cally receive a
system bootstrap (pointing to the device containing the
SP area) unless the first area allocated on the device is
preceded by an SK = nn (skip nn tracks) specification.
If an initial SK is not specified, the bootstrap is written
into sector 0 of track 0 and the first allocated area wi
II
begin at sector 1 (sector 2 for removable areas on cartridge/
disk).
All other areas allocated on the device, with the
possible exception of the BT area, will always start on
a track boundary.
If
default allocation is accepted for
CP and BT, BT will begin at the next available sector
following the CP area.
The CP area is not forced to
end on a track boundary unless it is explicitly allocated.
Note that an SK specification is ineffectual as a final param-
eter, i.e., if not followed by an area definition.
DEFAULT AREA ALLOCATION
The basi c system areas SP, SD, SL, CP, and BT may a
II
be
allocated by default, and in that order on the default device,
Alternatively the SP area may be specified explicitly and
the remaining four areas be allocated by default. Also, by
accepting default allocations and then selectively adding
explicit specifications, the user can relocate default areas,
change the default contents, and/or delete the SL, CP, or
BP areas as desi red, in addition to adding nondefault areas
to the defau
I
t devi ce.
Default allocations are selected by the user in either of
two ways:
1.
By specifying a system-default-allocation device, by
means of an liS" parameter in the de vi ce definition, e.g "
7204/80, S (for IIOP or IOP1, by default)
or
7204/80, S, E (for the EIOP or IOP2)
2.
By specif}'ing an SP area for a given device. In this
case, any of the other basi c system areas that were not
already explicitly specified will receive default allo-
cations on the device containing SP.
The liS "parameter takes precedence over the SP area speci-
fication;that is, default allocations may occur on some
device other than that which is to contain the SP area,
The order and extent of the areas allocated by default are
given in Table 11.
(The rules for lOP specifications and
defaults are given in Chapter 4.)
The device chosen to receive the system defaults via the
S parameter will automatically receive a system bootstrap
in sector O/trackO, and presumablywill be the IIsystem
device II unless the SP area is moved to another device by
a sl)bsequent, explicit SP area specification. Any of the
default area definitions can be superseded by subsequent
explicit specifications, allowing the default extents to
be modified, the order of the default .areas to be re-
arranged, and/or defau It areas to be deleted in case of
SL, CP, or BT (by setting their size to zero). Also, any
of the default areas may be moved to another disk by
Disk Storage Allocation Guidelines
21
Advertisement
Table of Contents
