r----- I Command
Name BACKSPAC CHANGE
CMD
DEFINE
DELETE DIS CONN DRAIN FLUSH FREE FWDSPACE HOLD MSG ORDER PURGE QUERY START TRACE
Function
Restart or reposition, in a backward direction, the file
currently being transmitted.
Alter one or more attributes of a file owned by Control certain functions performed by a remote system,
or control the logging of I/O activity on a specified
link.
Temporarily add a new link definition to the RSCS link
table or temporarily redefine an eXisting link.
Temporarily delete a link definition from the RSCS link
table. Place RSCS in disconnect mode and, optionally, direct
output to another virtual machine.
Deactivate an active communication link.
Discontinue processing the current file on the specified
link.
Resume transmission on a communication link previously
in HOLD status.
Reposition, in a forward direction, the file currently
being transmitted. Suspend file transmission on an active link without
deactivating the line. Send a message to a local or remote station.
Reorder files enqueued on a specific link.
Remove all or specified files from a link.
Request system information for a link, a file, or the
system in general.
Activate a specified communication link.
Monitor line activity on a specified link.
Figure 43. RSCS Command Summary A subset of the RSCS commands is available to the remote station
operators. In general, the remote operator can issue only those commands
that affect file processing at his specific link. The commands are
punched, one per card, and entered at the remote card reader. Commands
from remote stations are only accepted before the ID card of an input
card file or after the file has been completely processed (end of file
generated). Part 4. Remote Spooling communications Subsystem (RSCS) 331

Structure of RSCS Virtual Storage RSCS virtual storage is made up of
supervisor service routines
r system modules r and available free storage for
how RSCS storage is allocated.
fixed address storage
service modules# line
areas
r
driver
__ "'-: _ _ L _ _ , ... .- C1\.,.L..1.V\:: 1.C1::::>l\.::::>. Figure 44 shows Or -, 10000 r ,---------------- DMTVEC I / 270 1 I DMTKAP I I DMTCMX I 1----------------------\ DMTEXT I I DMTliGX I 1 I I DI1TSVC I I DMTCRE , I 1----------- I DMTIDK I , DMTCOM , I I 1 DMTQRQ I I DMTMSG I 1 I I DMTDSP I I DMTSYSI , 1 1---------- I DMTWAT I I DHTIHI2 , 1 , DMTPST I Free St::>rage I I I DMTASK / I / I DMTSTJ / I / I DMTASY / I I I DMTSIG I I I I DItTGIV I I I / I , DMTAKE 700001---------------- , 1---------------------1 , Third Line Driver I 10001 1 740001 , I Supervisor Queue Extension I , Second Lin' Driver I 20001 I 780001--- , I I 1 First Lin-' Dri.ver I I I ------1 I I I DMTL\x I I I 7DOOOI -------1 I Free storage I 1 DMTAXS 1 I (allocatable) I 80000 L- _____ J I I L lThe DKrSYS .odule can vary in size depending on the number of macros specified when the RSCS systea was generated. Free storage starts on the first page following the
end of DMTSYS. 2The DMTINI module is loaded at the beginning of the free storage area. After
initialization, the storage it occupied is freed and beco.es part of free storage.
Figure 44. RSCS Storage Allocation
332 IBM VM/370 System Programmer's Guide