FS ALLOCATEPAGESPACE: Difference between revisions

Revision as of 16:59, 21 May 2019

Adjust the size of paging file. Changes the size the paging file on disk.

Syntax

int far pascal FS_ALLOCATEPAGESPACE(psffsi, psffsd, ulsize, ulWantContig)

Parameters

psffsi: is a pointer to the file-system-independent portion of an open file instance.
psffsd: is a pointer to the file-system-dependent portion of an open file instance.
ulsize: is the desired new size of the paging file. If the new size is smaller than the current size, the excess space is released. If the new size is larger than the current size, the requested size is allocated.
ulWantContig: indicates the minimum contiguity requirement (in bytes)

Returns

Sample

struct sffsi far * psffsi;
struct sffsd far * psffsd;
unsigned long ulsize;
unsigned short ulWantContig;

int far pascal FS_ALLOCATEPAGESPACE(psffsi, psffsd, ulsize, ulWantContig)

Remarks

ulWantContig is a demand for contiguity. If ulWantContig is non-zero(0), the FSD must allocate any space in the swap file that is not contiguous in ulWantContig chunks on ulWantContig boundaries. If it is not possible to grow the file to ulSize bytes meeting the ulWantContig requirement, the operation should fail. If the file is being shrunk ulWantContig is irrelevant and should be ignored.

FSDs that support the paging I/O interface should be expected to be sensible in allocating page space. In particular, they are expected to always attempt to allocate space such that ulWantContig sized blocks on ulWantContig boundaries are physically contiguous on disk, and to keep the page file as a whole contiguous as possible.

@@ Line 1: / Line 1: @@
 {{DISPLAYTITLE:FS_ALLOCATEPAGESPACE}}
 Adjust the size of paging file. Changes the size the paging file on disk.
 ==Syntax==
   int far pascal FS_ALLOCATEPAGESPACE(psffsi, psffsd, ulsize, ulWantContig)
 ==Parameters==
-; psffsi: is a pointer to the file-system-independent portion of an open file instance.
+;psffsi: is a pointer to the file-system-independent portion of an open file instance.
-; psffsd: is a pointer to the file-system-dependent portion of an open file instance.
+;psffsd: is a pointer to the file-system-dependent portion of an open file instance.
-; ulsize: is the desired new size of the paging file. If the new size is smaller than the current size, the excess space is released. If the new size is larger than the current size, the requested size is allocated.
+;ulsize: is the desired new size of the paging file. If the new size is smaller than the current size, the excess space is released. If the new size is larger than the current size, the requested size is allocated.
-; ulWantContig: indicates the minimum contiguity requirement (in bytes)
+;ulWantContig: indicates the minimum contiguity requirement (in bytes)
 ==Returns==
@@ Line 19: / Line 19: @@
   int far pascal FS_ALLOCATEPAGESPACE(psffsi, psffsd, ulsize, ulWantContig)
 ==Remarks==
-ulWantContig is a demand for contiguity. If ulWantContig is non-zero(0), the FSD must allocate any space in the swap file that is not contiguous in ulWantContig chunks on ulWantContig boundaries. If it is not possible to grow the file to ulSize bytes meeting the ulWantContig requirement, the operation should fail . If the file is being shrunk ulWantContig is irrelevant and should be ignored .
+ulWantContig is a demand for contiguity. If ulWantContig is non-zero(0), the FSD must allocate any space in the swap file that is not contiguous in ulWantContig chunks on ulWantContig boundaries. If it is not possible to grow the file to ulSize bytes meeting the ulWantContig requirement, the operation should fail. If the file is being shrunk ulWantContig is irrelevant and should be ignored.
 FSDs that support the paging I/O interface should be expected to be sensible in allocating page space. In particular, they are expected to always attempt to allocate space such that ulWantContig sized blocks on ulWantContig boundaries are physically contiguous on disk, and to keep the page file as a whole contiguous as possible.
-[[Category:IFS]]