IBM System/370 145 Manual page 193

statements to OS job control s:tatements, and, depending on data
organization, conversion of DOS files to OS data sets. The amount
of reprogramming required'depe!nds on the source language being used.
In general, high-level languagre programs require much less
modification than Assembler La.nguage programs •
• The volume serial numbers of alII existing DOS direct access files
must be inspected for duplicat~es, and unique serial numbers should
be assigned where necessary. Volume serial numbers assigned to
newly created DOS files ~r OS data sets should be unique as well.
• The OS job stream should be planned, and consideration should be
given as to how OS DOS emulator jobs are to be scheduled and
executed, as discussed previously in this subsection;. Note also
that the total storage size of the DOS system being emulated may be
reduced. For example, if one DOS processing partition is devoted to
teleprocessing, CS/30 w or CS/40, which are not emulated by the OS
DOS emulator, this DOS partition is no longer required and its
storage can be made available for allocation to an OS partition or
region.
• Optionally, the size of the em.ulated DOS system can also be
~educed
by the removal of functions that are now provided by OS. For
example, DOS POWER can be removed from a DOS system, since data
transcription can be handled by the OS reader interpreter and output
writer. .The model-dependent DOS MCRR routine can be removed from a
DOS supervisor, as Model 145 MeH and CCH routines contained in the
as
control program will be used for machine and channel error
handling.
Note that alterations affecting the DOS supervisor normally
require a system generation to be performed. In addition, any
change resulting in a diffe.rent starting address for a DOS
partition means that existing nonrelocatable DOS programs
executing in that DOS parti·tion must be link-edited relative to
the new address.
Figure 40. 15 .. 1 illustrates a 256K Model 145 configurat.ion that
supports one OS processing partition (P2), a transient 44K reader
interpreter (P2), a resident output. writer (PO), and .emulation of a J28K
DOS system (P1) using the staged
1.10
option. The ISAM data set sharing
facility is not used.
Figure 40.15.2 illustrates a 160K Model 145 configuration that
supports one
as
proceSSing partition (P2), a transient 32K reader
interpreter (P2), a resident output writer (PO), and emulation of a 64K
DOS system (P1), of which only 48K need be emulated. The staged I/O
option and ISAM data set sharing alre not used.
The examples assume a m1n1mum Mj~ control program for the Model 145,
a minimum emulator program size, and a Model 145 configuration that
requires no more than 32K of control storage.
A Guide to the IBM System/370 Model 145
183