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Workbench Add-On - Volume 1.iso
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Programmers.doc
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1994-11-13
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234 lines
*****************************************************************
* *
* NOTE: IF YOU USE THE DISKSPARE.DEVICE FOR YOUR *
* PROGRAMS YOU HAVE TO COPY THIS DOC.FILE TOO !!!! *
* *
* Note: *
* I can only support your program in future releases *
* of the device, if you send me a FREE copy. *
* *
*****************************************************************
TABLE OF CONTENTS
diskspare.device/CMD_Remove
diskspare.device/CMD_GetGeometry
diskspare.device/CMD_RawRead
diskspare.device/CMD_RawWrite
diskspare.device/CMD_Eject
diskspare.device/Open
The other commands work like the corresponding trackdisk cmds.
KNOWN BUGS: * The value of dg_CylSectors returned by GetGeoMetry
is wrong.
Fixed in V2.0.
* The Device doesn't support ETD_Cmds correctly.
Fixed in V2.1.
* The Device returns an Error IOERR_BADADDRESS
if the adress of IO_DATA is odd (PFS only).
Fixed in V2.1.
* If remove is called twice, the System crashes.
Fixed in V2.1.
* Error in CloseDevice: Maybe a RemPort on a Port
which wasn't added -> Crash (caused by register mistake)
Fixed in V2.1
* Error in TD_FORMAT: Doesn't do an Update but flushes
the trackbuffer. (PFS only)
Fixed in V2.2
* It was possible to read/write beyond the last track.
Fixed in V3.0
* Error in CMD_READ: Trackbuffer not cleared although disk
changed. (PFS only)
Fixed in V3.0
* Enforcer hit in initport.
Fixed in V3.0
NAME Remove
FUNCTION If you are not the FastFileSystem, and I guess
you aren't, NEVER call Remove !
It's no use calling Remove !!
The best thing is to forget that there's a
cmd called Remove !!!
IF you call this forgotten cmd and the DD<>HD
autoswitch is enabled (Bit 2 in Flags is set), the
system WILL crash !!!!
If you want to add a diskchange-int, use the
addchangeint/remchangeint cmd instead.
Why was this patch necessary ?
Because there's a restriction in the FFS: It checks,
if the devicename is 'trackdisk.device' and if it
isn't, GetGeometry won't be called.
I tried to fix the disksize in the dosenvec-struct
and all programs like FixDisk, DiskSalv, Format etc
worked fine. BUT the FFS said 'Not a DOS Disk'...
SEE ALSO Includes/exec/alerts.i
BUGS If Remove was called twice, the System crashed.
Fixed in V2.1.
NAME GetGeometry
FUNCTION Works like trackdisk.
There are two possibilities for Sectors per Track:
12 sectors/track and 24 sectors/track.
You have to check this after each diskchange !
New for V3.0:
You get always the right disksize.
The HD mode always works (with HD drives).
Please check version number.
SEE ALSO AutoDocs/trackdisk.doc
BUGS There was a bug in the first release (V1.6):
The value returned in dg_CylSectors was wrong.
I forgot an 'ext.l', so the contents of the
high order word was rubbish. Fixed in V2.0.
NAME RawRead
FUNCTION No Function ! Returns IOERR_NOCMD. Use trackdisk
device for rawread.
NAME RawWrite
FUNCTION No Function ! Returns IOERR_NOCMD. Use trackdisk
device for rawwrite.
NAME Eject
FUNCTION No Function ! Returns IOERR_NOCMD. Use trackdisk
device to eject (if you've got a drive which ejects).
NAME OpenDevice
FUNCTION Opens the device with a drive-specific set of flags.
There's something special about the flags:
If the device wasn't opened yet, everything works as
usual. If the device was already opened (via Mount)
your flags will be ignored, but the device won't
return an error. (Some well known programs crash
when an OPENFAIL was returned ??? They obviously
don't use the fssm_Flags when opening AND don't
check for errors ?¿?)
The active flags are returned in IO_ACTUAL. So you
can check whether the flags fit your needs or not.
Why ?
If the user has mounted the device with HighCyl = 79
then it's his decision not to use it and you HAVE TO
accept that. It's the users Amiga not yours.
The minimum you get is:
heads: 2
tracks: 160
sectors/track: 12/24
bytes/sector: 512
# of sectors: 1920/3840
total bytes: 983040/1966080
SEE ALSO AutoDocs/exec.doc/opendevice
FLAGS
BIT 0 0: disable diskchange for DFX:
1: enable diskchange for DFX:
Works only when mounting the device with the FastFileSystem.
When you open the device and don't call the forgotten
cmd the diskchange-int of the corresponding trackdisk
drive won't be affected.
BIT 1 0: HighCyl is Cyl. 79
1: HighCyl is Cyl. 81
When set to '1' trackdisk WILL be patched everytime a
track is read/written from/to disk!
BIT 2 0: DD and HD mode are now available.
That's new. Check the device version.
1: Autodetection of DD/HD-disks for the
FastFileSystem, too. It is patched.
Call GetGeometry to get the right disksize. See above.
The patch for the ffs is in the remove cmd. So if you
open without bit 1 set and don't call the forgotten cmd
NOTHING is patched !!
Version 2.2:
BIT 3 0: Use any Mem for trackbuffer
1: Try to use Mem from $600000 - $A00000
If there's no memory at this location
any other mem is used.
Why ? I've got an A2000 with A2630 (which has it's mem at
$200000-$5FFFFF) and a 16bit Ramcard at $600000 - $A00000.
So why should I use the 32bit ram (which is prefered when
calling allocmem) for a trackbuffer ?
This bit may be useful for A3/4000 with 16bit ramboards too.
Version 3.0:
BIT 3 isn't used.
Version 3.0:
BIT 4 0: Normal write mode.
1: Verify write mode. Each write will be
verfied by the device itself. This nearly
half the write speed but you're sure the
data on disk is ok. Useful with cheap
disks.
BIT 5-31 are currently unused and RESERVED.
NOTES
HD-Mode:
To check if the drive is a highdensity one you may call
GetUnitID from the disk.resource. Here are the Results:
No Disk in any Drive -> returns 0x00000000
Any Disk in a DD Drive -> returns 0x00000000
A DD-Disk in a HD Drive -> returns 0x00000000
A HD-Disk in a HD Drive -> returns 0xAAAAAAAA
No Drive connected -> returns 0xFFFFFFFF
As you can see, it's not possible to check if the drive
is a hd one, if there's no HD Disk in it.
Don't care about that. Simply call GetGeometry to get the
right disksize. BUT it may be differently for each disk (DD/HD).
AddChangeInt:
If you've already added a ChangeInt with the trackdisk.device,
you needn't add one with diskspare.device because it's directly
passed through to the trackdisk.device.
Inhibit:
It's a good idea to inhibit the corresponding trackdisk drive
(DFX) when accessing the disk via diskspare.device. Also
check for mounted diskspare drives. Don't rely on the names
DS0: to DS3: when you inhibit the DOS.
The device itself can't inhibit the DOS because a task isn't
allowed to call a dos.lib function.
General:
The main purpose of this device is to be mounted with the
FastFileSystem. So always remember that you may not be the
only accessor !!