Before the LOADSYS 320K_.------------------_ I I I I I I , l I All Storage Addressable by Virtual ftachine I ,. CftS virtual ftachine without a la.ed Seg.ent Attached
After LOADSYS Function
_ ______ ____ _
448K_.------------------------, I Discontiguous Storage I Addressable by Virtual I ftachine .///////////////////////// . • /Storage lot Addressable/ • • ///by Virtual ftachine//// • . /////////////////////////. 320K I • I l I I I I I Storage Still I I Addressable by I I Virtual ftachine I I I I , , , OK' I CftS Virtual ftachine with a la.ed Seg.ent Attached Before and After a LOADSYS Function When you save a na.ed seg.ent that is later loaded by the LOADSYS function, you .ust be sure that the addresses at which seg.ents are
saved are correct and that they do not overlay required areas of storage
in the virtual .achine. This is crucial because the LOADSYS function
invokes the PURGESYS function before it builds the new page and swap tables. CP purges all saved syste.s that are overlayed in any way by
the saved syste. it is loading. 1 condition code of 0 in the PSW indicates that the na.ed seg.ent was loaded successfully; the Rx register contains the load address. A condition code of 1 in the PSi indicates the na.ed seg.ent was loaded successfully within the defined storage of the virtual .achine.
The Rx register contains the address at which the na.ed seg.ent was loaded. The Ry register contains the ending address of the storage
released before the na.ed segment Was loaded.
Bote: CftS only allows naaed segments to be attached beyond the defined
size of the virtual .achine. A condition code of 2 in the PSi indicates the LOADSYS function did
not execute successfully. Examine the return code in the Ry register to
deter.ine the cause of the error.
Return Code ---"4--- 177 fteani,!!g Ba.ed seg.ent does not exist
Paging I/O errors When the PURGESYS function
associated page and swap is executed; CP
tables, that
releases the storage, and
were acquired when the
1-68 IB! V!/370 Syste. Logic and Problem Deter.ination--Volu.e 1

corresponding L01DSYS function was executed. If the storage occupied by
the named segment was beyond the defined virtual machine storage size,
that storage is no longer addressable by the virtual machine. When a PUBGESYS function is executed for a segment that was loaded in
nonshared .ode, the storage area is cleared to binary zeros. If PUBGESYS is invoked for a named segment that was not previously loaded
via L01DSYS, the request is ignored. 1 condition code of 0 in the PSW indicates successful completion. 1 condition code of 1 in the PSW indicates that the named segment was not found in the virtual machine. 1 condition code of 2 in the PSI and a return code of 44 in the By
register indicate that the named segment either does not exist or was not previously loaded via the L01DSYS function. When the FIHDSYS function is executed, CP checks that the named segment exists and that it has not been loaded previously. 1 condition code of 0 in the PSI indicates that the naaed segment is
already loaded. The address at which it was loaded is returned in the
register specified as Bx and its highest address is returned in the By
register. 1 condition code of 1 in the PSi indicates that the named segment exists but has not been loaded.. In this case, the address at which the named segment is to be loaded is returned in the register specified as Bx and the highest address of the named segment is returned in the By register. 1 condition code of 2 in the PSi indicates the FIIDSYS function did
not execute successfully. Exaaine the return code in the By register to
deter.ine the error that occurred. Betu:t1! 44 177 !hl!aning Hamed-segment does not exist Paging I/O errors £2de == Virtyal lachine FacilitI The DIIGBOSE code 1'68' is used by a virtual machine to initiate a
subfunction of the Virtual !achine Communication Pacility (V!CP). The general register specified as Bx contains the virtual address,
doubleword aligned, of a parameter list (VSCPIB!). One of the entries
in this parameter list is a sub function code, specifying the particular
request being initiated. The subfunctions and their codes are:
CP Introduction 1-69