Device Driver (Strategy 1) Request Packet (REQ)

>> The two request packet pools for general device driver use:

##.moc 93

*har     par      cpg        va    flg next prev link hash hob   hal
 0091 %feaefc80 00000010 %ab546000 129 0090 0092 0000 0000 0093 0000   sel=04a8
 hob   har hobnxt flgs own  hmte  sown,cnt lt st xf
 0093  0091 0000  0124 ff40 0000  0000 00  00 00 00 reqpkt1
##.moc 94

*har     par      cpg        va    flg next prev link hash hob   hal
 0092 %feaefc96 00000010 %ab536000 129 0091 0093 0000 0000 0094 0000   sel=04b0
 hob   har hobnxt flgs own  hmte  sown,cnt lt st xf
 0094  0092 0000  0124 ff33 0000  0000 00  00 00 00 reqpkt2



>> Formatting the request packet assigned to slot 43:

##.p#
 Slot  Pid  Ppid Csid Ord  Sta Pri  pTSD     pPTDA    pTCB     Disp SG Name
*0043# 000d 0004 000d 0005 blk 081f ab7fb000 ab99ac20 ab97f220 1d24 17 faxworks

##dd %ab97f220 +1ac l1
%ab97f3cc  04a80832

##.d req 4a8:832
           PktLen: 2c
          PktUnit: 00
           PktCmd: 04
        PktStatus: 0000
       PktDOSLink: 00000000
       PktDevLink: 00000000
          IOmedia: 00
          IOpData: 008f7883
          IOcount: 0000
          IOstart: 00000000


>> Formatting the request packet assigned to slot 2:

##.p2
 Slot  Pid  Ppid Csid Ord  Sta Pri  pTSD     pPTDA    pTCB     Disp SG Name
 0002  0001 0000 0000 0002 blk 0200 ab779000 ffe3ca00 ab977020 1f3c 00 *tsd
##dd %ab977020 +1ac l1
%ab9771cc  04a80012
##.d req 4a8:12
           PktLen: 32
          PktUnit: 00
           PktCmd: 00
        PktStatus: 0000
       PktDOSLink: 00000000
       PktDevLink: 00000000
        InitcUnit: 00
       InitDevHlp: 0000:0000
        InitParms: 0000:0000
          InitDrv: 00
     InitSysiData: 0000
##

Notes:

Request Packets are allocated from one of three pools:

Strategy 1 request pool

Strategy 2 request pool

Swapper request pool

Each thread is pre-assigned a strategy 1 request packet. If this is in use when a device driver tries to allocate another then a packet is allocated from the strategy 2 pool for strategy 1 use.

Asynchronous Read and Write requests are implemented in DOSCALL1.DLL by creating multiple threads on which to run the parallel I/O requests.

• D REQ does not format Strategy 2 format Request Packets.

For a description of the Request Packet fields see the Device Driver Request Packer in the System Reference.