Changeset 230

Timestamp:

Jan 8, 2011, 11:09:12 PM (15 years ago)

Author:

dmik

Message:

README.OS2: Wording.

File:

• trunk/doc/README.OS2 (modified) (4 diffs)

trunk/doc/README.OS2

@@ -91 +91 @@
 
   Note that these values are gathered on a default eCS 2.0 GA system and may
-  vary depending on what system DLLs get loaded into each process, they are
+  vary depending on what system DLLs get loaded into each process; they are
   given only as an example. You may get the real values on your system with
   a variety of tools gathering system information, such as THESEUS.
 
   On the other hand, when calculating the default amount of memory to reserve
-  for the the heap (which is called the maximum heap size in the documentation),
+  for the heap (which is called the maximum heap size in the documentation),
   Java uses the physical RAM size as a base, not the the size of the free block
   in the private arena (where Java actually allocates the heap). Below is a
   simplified version of the algorithm for these calculations:
 
-  1. Use MIN (MaxRAM, <physical_RAM>) as the base RAM value. MaxRAM is a Java[
-     constant that defaults to 1G for the client (regular) Java virtual machine
-     and 4G for the server JVM.
+  1. Use MIN (MaxRAM, <physical_RAM>) as the base RAM value. MaxRAM is a Java
+     constant that defaults to 1G for the client (default) Java virtual machine
+     and to 4G for the server JVM.
 
   2. Divide this base RAM value by MaxRAMFraction (4 by default) and assign the
@@ -109 +109 @@
 
   3. Use the MaxHeapSize value increased by 20-30% (for the needs other than the
-     Java heap) as the size of the private memory block to allocate.
+     Java heap) as the size of the memory block to allocate in the private
+     arena.
 
   So, if your machine has, say, 2G of RAM and you attempt to start it in server
@@ -121 +122 @@
   limiting the amount of memory Java wants for the heap to the actual size of
   the available memory block in the private arena. So, in the above case Java
-  would actually get about 310M in server mode (instead of the requested 512M).
-  You may change this limit by changing VIRTUALADDRESSLIMIT in CONFIG.SYS
-  (according to the table above), but please note that values higher than 1024
-  may cause problems with some drivers (for example, it is known that JFS and
-  HPFS386 drivers cannot allocate a disk cache of the big size if the
-  VIRTUALADDRESSLIMIT value is too high).
+  would actually get about 310M in server mode (instead of performing a failed
+  attempt to allocate 512M). You may change this limit by changing the
+  VIRTUALADDRESSLIMIT value in CONFIG.SYS (according to the table above), but
+  please note that values higher than 1024 may cause problems with some drivers
+  (for example, it is known that JFS and HPFS386 drivers cannot allocate a disk
+  cache of the big size if the VIRTUALADDRESSLIMIT value is too high).
 
   In either case, the above describes how Java calculates the defaulut maximum
@@ -132 +133 @@
   command line option if you are not satisfied with the default value for some
   reason or if your applcation gives you the "Could not reserve enough space for
-  object heap" message at startup. However, keep in mind that if you a -Xmx
-  value which is bigger than the maximum free block in the private arena, you
-  will get the same error and will have to decrease the requested size until it
-  succeeds.
+  object heap" message at startup. However, keep in mind that if you specify a
+  -Xmx value which is, increased by 20-30% as described in step 3 above, bigger
+  than the maximum free block in the private arena, you will get the same memory
+  allocation error which indicates that you should use a smaller value.