VIRTUAL STORAGE DMSFREE requests when
no more low available FREELOWE
Unused portion of User
T Program Area T MAINHIGH --t -------- 7v.:.. MAINSTRT ____ [ The User's Program
(program is loaded via the LOAD commandl __________________ CMS Nucleus In "saved systems" this area
is a protected segment
(that is, all code must be
reentrant and cannot be
modified) Transient Program Area X'EOOO' Low Stor* DMSFREE Free Area DMSFREE requests are filled from
this area. The upper part of this
area contains the System Disk MFD followed by the FREETAB, if there is
enough room. DMSNUC and pointers.
has a storage key = X'E' fiqure 27. CM S Storaqe Map
April 1, 1981 CONTROL BLOCKS ! LORST I I I R I I BEJG X'2A40' X'29SO' X'235O' X'23OO' X'219O' X'1DDO'
X'1CCS' FVS X'1ADS' DIOSECT X'19ES' SVCSECT X'1748'
X'16BO'
X'1620'
X'1550' X'1200' X'DFO'
------------i X'2EO' Part 3. Conversational Monitor System (CMS) 245
Paqe of GC20-1807-7 As Updated April 1, 1981 by TNL GN25-0829
The format of an element on the GETMAIN free element chain is as
follows:
r I o (0) I 1 4 (4) , i i
FREPTR --pointer to next free
element in the chain, or 0 if there is no next element
---i I 1---- FRELEN --length, in bytes, of
this element
-----i i 1------- Remainder of this free element
The amount of storage reserved for eMS use is determined at eMS IPL
time based on the size of the virtual machine. The formula for
calculating this reserved storage is:
Less than 512K
512K
Greater than 512K 10 pages
12 pages + 2 pages for each
256K in excess of 512K
12 pages + 2 pages for each
256K in excess of 512K
246 IBM VM/370 System Programmer's Guide
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