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<TITLE>Int 21/AH=0Fh
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Int 21/AH=0Fh - DOS 1+ - OPEN FILE USING FCB -
AH = 0Fh
DS:DX - unopened File Control Block (see #01345,#01346)
Return: AL = status
00h successful
FFh file not found or access denied
Notes: (DOS 3.1+) file opened for read/write in compatibility mode
an unopened FCB has the drive, filename, and extension fields filled
in and all other bytes cleared
not supported by MS Windows 3.0 DOSX.EXE DOS extender
DR DOS checks password attached with AX=4303h
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<h2>Int 21/AH=0Fh
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<h3><font color=#C00040>DOS 1+ - OPEN FILE USING FCB</font></h3>
<PRE>
AH = 0Fh
DS:DX -> unopened File Control Block <a href="javascript:if(confirm('http://www.ctyme.com/intr/rb-0000.htm \n\nThis file was not retrieved by Teleport Pro, because it was unavailable, or its retrieval was aborted, or the project was stopped too soon. \n\nDo you want to open it from the server?'))window.location='http://www.ctyme.com/intr/rb-0000.htm#Table0'" tppabs="http://www.ctyme.com/intr/rb-0000.htm#Table0"></a>(see #01345,#01346)<br>
<p><b>Return:</b><br>AL = status
00h successful
FFh file not found or access denied
</PRE>
<p><b>Notes:</b>
(DOS 3.1+) file opened for read/write in compatibility mode.
An unopened FCB has the drive, filename, and extension fields filled
in and all other bytes cleared.
Not supported by MS Windows 3.0 DOSX.EXE DOS extender.
DR DOS checks password attached with AX=4303h.
(FAT32 drive) this function will only succeed for creating a volume
label; FAT32 does not support FCBs for file I/O
<p><b>BUG:</b>
APPEND for DOS 3.3+ corrupts DX if the file is not found
<p><b>See Also:</b>
<a href="rb-2575.htm" tppabs="http://www.ctyme.com/intr/rb-2575.htm">AH=10h</a> - <a href="rb-2581.htm" tppabs="http://www.ctyme.com/intr/rb-2581.htm">AH=16h</a> - <a href="rb-2779.htm" tppabs="http://www.ctyme.com/intr/rb-2779.htm">AH=3Dh</a> - <a href="rb-2806.htm" tppabs="http://www.ctyme.com/intr/rb-2806.htm">AX=4303h</a>
<PRE>
<p>
Format of File Control Block:
<a name=table1345></a>
Offset Size Description (Table 01345)
00h BYTE drive number (0 = default, 1 = A, etc)
FFh is not allowed (signals extended FCB, see #01346)
01h 8 BYTEs blank-padded file name
09h 3 BYTEs blank-padded file extension
0Ch WORD current block number
0Eh WORD logical record size
10h DWORD file size
14h WORD date of last write <a href="javascript:if(confirm('http://www.ctyme.com/intr/rb-0000.htm \n\nThis file was not retrieved by Teleport Pro, because it was unavailable, or its retrieval was aborted, or the project was stopped too soon. \n\nDo you want to open it from the server?'))window.location='http://www.ctyme.com/intr/rb-0000.htm#Table0'" tppabs="http://www.ctyme.com/intr/rb-0000.htm#Table0"></a>(see #01666 at AX=5700h)
16h WORD time of last write <a href="javascript:if(confirm('http://www.ctyme.com/intr/rb-0000.htm \n\nThis file was not retrieved by Teleport Pro, because it was unavailable, or its retrieval was aborted, or the project was stopped too soon. \n\nDo you want to open it from the server?'))window.location='http://www.ctyme.com/intr/rb-0000.htm#Table0'" tppabs="http://www.ctyme.com/intr/rb-0000.htm#Table0"></a>(see #01665 at AX=5700h) (DOS 1.1+)
18h 8 BYTEs reserved <a href="javascript:if(confirm('http://www.ctyme.com/intr/rb-0000.htm \n\nThis file was not retrieved by Teleport Pro, because it was unavailable, or its retrieval was aborted, or the project was stopped too soon. \n\nDo you want to open it from the server?'))window.location='http://www.ctyme.com/intr/rb-0000.htm#Table0'" tppabs="http://www.ctyme.com/intr/rb-0000.htm#Table0"></a>(see #01347,#01348,#01349,#01350,#01351)
20h BYTE record within current block
21h DWORD random access record number (if record size is > 64 bytes, high
byte is omitted)
</PRE>
<p><b>See Also:</b>
#01346
<PRE>
<p>
Format of Extended File Control Block (XFCB):
<a name=table1346></a>
Offset Size Description (Table 01346)
00h BYTE FFh signature for extended FCB
01h 5 BYTEs reserved
06h BYTE file attribute if extended FCB
07h 36 BYTEs standard FCB (all offsets are shifted by seven bytes)
</PRE>
<p><b>See Also:</b>
#01246
<PRE>
<p>
Format of FCB reserved field for DOS 1.0:
<a name=table1347></a>
Offset Size Description (Table 01347)
16h WORD location in directory (if high byte = FFh, low byte is device
ID)
18h WORD number of first cluster in file
1Ah WORD current absolute cluster number on disk
1Ch WORD current relative cluster number within file
(0 = first cluster of file, 1 = second cluster, etc.)
1Eh BYTE dirty flag (00h = not dirty)
1Fh BYTE unused
<p>
Format of FCB reserved field for DOS 1.10-1.25:
<a name=table1348></a>
Offset Size Description (Table 01348)
<p><b>18h BYTE bit 7:</b><br>Set if logical device
<p><b>bit 6:</b><br>Not dirty
<p><b>bits 5-0:</b><br>Disk number or logical device ID
19h WORD starting cluster number on disk
1Bh WORD current absolute cluster number on disk
1Dh WORD current relative cluster number within file
1Fh BYTE unused
<p>
Format of FCB reserved field for DOS 2.x:
<a name=table1349></a>
Offset Size Description (Table 01349)
<p><b>18h BYTE bit 7:</b><br>Set if logical device
<p><b>bit 6:</b><br>Set if open???
<p><b>bits 5-0:</b><br>???
19h WORD starting cluster number on disk
1Bh WORD ???
1Dh BYTE ???
1Eh BYTE ???
1Fh BYTE ???
<p>
Format of FCB reserved field for DOS 3.x:
<a name=table1350></a>
Offset Size Description (Table 01350)
18h BYTE number of system file table entry for file
19h BYTE attributes
<p><b>bits 7,6:</b><br>00 = SHARE.EXE not loaded, disk file
01 = SHARE.EXE not loaded, character device
10 = SHARE.EXE loaded, remote file
11 = SHARE.EXE loaded, local file or device
<p><b>bits 5-0:</b><br>Low six bits of device attribute word
---SHARE.EXE loaded, local file---
1Ah WORD starting cluster of file on disk
1Ch WORD (DOS 3.x) offset within SHARE of sharing record
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1Eh BYTE file attribute
1Fh BYTE ???
---SHARE.EXE loaded, remote file---
1Ah WORD number of sector containing directory entry <a href="rb-2576.htm#Table1352" tppabs="http://www.ctyme.com/intr/rb-2576.htm#Table1352">(see #01352)</a>
1Ch WORD relative cluster within file of last cluster accessed
1Eh BYTE absolute cluster number of last cluster accessed
1Fh BYTE ???
---SHARE.EXE not loaded---
1Ah BYTE (low byte of device attribute word AND 0Ch) OR open mode
1Bh WORD starting cluster of file
1Dh WORD number of sector containing directory entry <a href="rb-2576.htm#Table1352" tppabs="http://www.ctyme.com/intr/rb-2576.htm#Table1352">(see #01352)</a>
1Fh BYTE number of directory entry within sector
</PRE>
<p><b>Note:</b>
If FCB opened on character device, DWORD at 1Ah is set to the address
of the device driver header, then the BYTE at 1Ah is overwritten.
<p><b>See Also:</b>
#01646
<PRE>
<p>
Format of FCB reserved field for DOS 5.0:
<a name=table1351></a>
Offset Size Description (Table 01351)
18h BYTE number of system file table entry for file
19h BYTE attributes
<p><b>bits 7,6:</b><br>00 = SHARE.EXE not loaded, disk file
01 = SHARE.EXE not loaded, character device
10 = SHARE.EXE loaded, remote file
11 = SHARE.EXE loaded, local file or device
<p><b>bits 5-0:</b><br>Low six bits of device attribute word
---SHARE.EXE loaded, local file---
1Ah WORD starting cluster of file on disk
1Ch WORD unique sequence number of sharing record
1Eh BYTE file attributes
1Fh BYTE unused???
---SHARE.EXE loaded, remote file---
1Ah WORD network handle
1Ch DWORD network ID
---SHARE not loaded, local device---
1Ah DWORD pointer to device driver header <a href="rb-2983.htm#Table1646" tppabs="http://www.ctyme.com/intr/rb-2983.htm#Table1646">(see #01646)</a>
1Eh 2 BYTEs unused???
---SHARE not loaded, local file---
1Ah BYTE extra info
<p><b>bit 7:</b><br>Read-only attribute from SFT
<p><b>bit 6:</b><br>Archive attribute from SFT
<p><b>bits 5-0:</b><br>High bits of sector number
1Bh WORD starting cluster of file
1Dh WORD low word of sector number containing directory entry
<a href="rb-2576.htm#Table1352" tppabs="http://www.ctyme.com/intr/rb-2576.htm#Table1352">(see #01352)</a>
1Fh BYTE number of directory entry within sector
</PRE>
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<b>Category: <a href="cat-010.htm" tppabs="http://www.ctyme.com/intr/cat-010.htm">
DOS Kernel</a>
- <a href="int-21.htm" tppabs="http://www.ctyme.com/intr/int-21.htm">
Int 21h</a>
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