Block devices are nonvolatile mass storage devices whose information can be accessed in any order. Examples of block devices include hard disks, floppy disks, and CD-ROMs. OpenBoot typically uses block devices for booting.
This device type generally applies to disk devices, but as far as OpenBoot is concerned, it simply means that the device "looks like a disk" at the OpenBoot software interface level.
The block device's FCode must declare the block device type, and implement the methods open and close, as well as the methods described in "Required Methods" on page 84.
Although packages of the block device type present a byte-oriented interface to the rest of the system, the associated hardware devices are usually block- oriented i.e. the device reads and writes data in blocks (groups of, for example, 512 or 2048 bytes). The standard /deblocker support package assists in the presentation of a byte-oriented interface overlaying a block-oriented interface, implementing a buffering layer that hides the underlying block length.
Block devices are often subdivided into several logical partitions, as defined by a disk label - a special block, usually the first one on the device, which contains information about the device. The driver is responsible for appropriately interpreting a disk label. The driver may use the standard /disk-label support package if the device does not implement a specialized label. The /disk-label support package interprets a system-dependent label format. Since the disk booting protocol usually depends on the label format, the standard /disk-label support package also implements a load method for the corresponding boot protocol.
Byte devices are sequential-access mass storage devices, for example tape devices. OpenBoot typically uses byte devices for booting.
The byte device's FCode program must declare the byte device type, and implement the open and close methods in addition to those described in "Required Methods".
Although packages of the byte device type present a byte-oriented interface to the rest of the system, the associated hardware devices are usually record- oriented; the device reads and writes data in records containing more than one byte. The records may be fixed or variable length. The standard /deblocker support package assists in presenting a byte-oriented interface overlaying a record-oriented interface, implementing a buffering layer that hides the underlying record structure.
Table 6-1 Required Properties of Block and Byte Devices
----------------------------------------------------
Property Name Sample Value ----------------------------------------------------
name " SUNW,my-scsi"
reg list of registers (device-dependent)
device_type block or byte
----------------------------------------------------
The structure of the device tree for the sample card supported by the sample device drivers in this chapter is as follows:
Figure 6-1 Sample Device Tree
Code Example 1 Simple Block Device Driver
-----------------------------------------------------------------------------------
\ This is at a stage where each leaf node can be used only as a non-bootable device. \ It only creates nodes and publishes necessary properties to identify the device. hex " SUNW,my-scsi" encode-string " name" property h# 20.0000 constant scsi-offset h# 40 constant /scsi my-address scsi-offset + my-space /scsi reg new-device \ missing "reg" indicates a SCSI "wild-card" node " sd" encode-string " name" property finish-device new-device \ missing "reg" indicates a SCSI "wild-card" node " st" encode-string " name" property finish-device end0 -----------------------------------------------------------------------------------
Code Example 2 Sample Driver for my-scsi Device
-------------------------------------------------------------------------------------------
\ sample driver for "my-scsi" device.
\ It is still a non-bootable device. The purpose is to show how an intermediate stage
\ of driver can be used to debug board during development. In addition to publishing
\ the properties, this sample driver shows methods to access, test and control
\ "SUNW,my-scsi" device.
\ The following main methods are provided for "SUNW,my-scsi" device.
\ open ( -- okay? )
\ close ( -- )
\ reset ( -- )
\ selftest ( -- error? )
hex
headers
h# 20.0000 constant scsi-offset
h# 40 constant /scsi
d# 25.000.000 constant clock-frequency
: identify-me ( -- )
" SUNW,my-scsi" encode-string " name" property
" scsi" device-type
my-address scsi-offset + my-space /scsi reg
;
identify-me
h# 10.0000 constant dma-offset
h# 10 constant /dma
-1 instance value dma-chip
\ methods to access/control dma registers
: dmaaddress ( -- addr ) dma-chip 4 + ;
: dmacount ( -- addr ) dma-chip 8 + ;
: dmaaddr@ ( -- n ) dmaaddress rl@ ;
: dmaaddr! ( n -- ) dmaaddress rl! ;
: dmacount@ ( -- n ) dmacount rl@ ;
: dmacount! ( n -- ) dmacount rl! ;
: dma-chip@ ( -- n ) dma-chip rl@ ;
: dma-chip! ( n -- ) dma-chip rl! ;
: dma-btest ( mask -- flag ) dma-chip@ and ;
: dma-bset ( mask -- ) dma-chip@ or dma-chip! ;
: dma-breset ( mask -- ) not dma-btest dma-chip! ;
external
\ methods to allocate, map, unmap, free dma buffers
: decode-unit ( addr len -- low high ) decode-2int ;
: dma-alloc ( size -- vaddr ) " dma-alloc" $call-parent ;
: dma-free ( vaddr size -- ) " dma-free" $call-parent ;
: dma-map-in ( vaddr size cache? -- devaddr ) " dma-map-in" $call-parent ;
: dma-map-out ( vaddr devaddr size -- ) " dma-map-out" $call-parent ;
\ Dma-sync could be a dummy routine if the parent device doesn't support.
: dma-sync ( virt-addr dev-addr size -- )
" dma-sync" my-parent ['] $call-method catch if
2drop 2drop 2drop
then
;
: map-in ( addr space size -- virt ) " map-in" $call-parent ;
: map-out ( virt size -- ) " map-out" $call-parent ;
headers
: dma-open ( -- )
my-address dma-offset + my-space /dma map-in to dma-chip
;
: dma-close ( -- ) dma-chip /dma map-out -1 to dma-chip ;
-1 instance value scsi-init-id
-1 instance value scsi-chip
h# 20 constant /mbuf
-1 instance value mbuf
-1 instance value mbuf-dma
d# 6 constant /sense
-1 instance value sense-command
-1 instance value sense-cmd-dma
d# 8 constant #sense-bytes
-1 instance value sense-buf
-1 instance value sense-buf-dma
-1 instance value mbuf0
d# 12 constant /cmdbuf
-1 instance value cmdbuf
-1 instance value cmdbuf-dma
-1 instance value scsi-statbuf
\ mapping and allocation routines for scsi
: map-scsi-chip ( -- )
my-address scsi-offset + my-space /scsi map-in to scsi-chip
;
: unmap-scsi-chip ( -- ) scsi-chip /scsi map-out -1 to scsi-chip ;
\ After any changes to sense-command by CPU or any changes to sense-cmd-dma by
\ device, synchronize changes by issuing " sense-command sense-cmd-dma /sense
\ dma-sync " Similarly after any changes to sense-buf, sense-buf-dma, mbuf,
\ mbuf-dma, cmdbuf or cmdbuf-dma, synchronize changes by appropriately issuing
\ dma-sync map scsi chip and allocate buffers for "sense" command and status
: map-scsi ( -- )
map-scsi-chip
/sense dma-alloc to sense-command
sense-command /sense false dma-map-in to sense-cmd-dma
#sense-bytes dma-alloc to sense-buf
sense-buf #sense-bytes false dma-map-in to sense-buf-dma
2 alloc-mem to scsi-statbuf
;
\ free buffers for "sense" command and status and unmap scsi chip
: unmap-scsi ( -- )
scsi-statbuf 2 free-mem
sense-buf sense-buf-dma #sense-bytes dma-sync \ redundant
sense-buf sense-buf-dma #sense-bytes dma-map-out
sense-buf #sense-bytes dma-free
sense-command sense-cmd-dma /sense dma-sync \ redundant
sense-command sense-cmd-dma /sense dma-map-out
sense-command /sense dma-free
-1 to sense-command
-1 to sense-cmd-dma
-1 to sense-buf
-1 to scsi-statbuf
-1 to sense-buf-dma
unmap-scsi-chip
;
\ constants related to scsi commands
h# 0 constant nop
h# 1 constant flush-fifo
h# 2 constant reset-chip
h# 3 constant reset-scsi
h# 80 constant dma-nop
\ words to get scsi register addresses.
\ Each chip register is one byte, aligned on a 4-byte boundary.
: scsi+ ( offset -- addr ) scsi-chip + ;
: transfer-count-lo ( -- addr ) h# 0 scsi+ ;
: transfer-count-hi ( -- addr ) h# 4 scsi+ ;
: fifo ( -- addr ) h# 8 scsi+ ;
: command ( -- addr ) h# c scsi+ ;
: configuration ( -- addr ) h# 20 scsi+ ;
: scsi-test-reg ( -- addr ) h# 28 scsi+ ;
\ Read only registers:
: scsi-status ( -- addr ) h# 10 scsi+ ;
: interrupt-status ( -- addr ) h# 14 scsi+ ;
: sequence-step ( -- addr ) h# 18 scsi+ ;
: fifo-flags ( -- addr ) h# 1c scsi+ ;
\ Write only registers:
: select/reconnect-bus-id ( -- addr ) h# 10 scsi+ ;
: select/reconnect-timeout ( -- addr ) h# 14 scsi+ ;
: sync-period ( -- addr ) h# 18 scsi+ ;
: sync-offset ( -- addr ) h# 1c scsi+ ;
: clock-conversion-factor ( -- addr ) h# 24 scsi+ ;
\ words to read from/store to scsi registers.
: cnt@ ( -- w ) transfer-count-lo rb@ transfer-count-hi rb@ bwjoin ;
: fifo@ ( -- c ) fifo rb@ ;
: cmd@ ( -- c ) command rb@ ;
: stat@ ( -- c ) scsi-status rb@ ;
: istat@ ( -- c ) interrupt-status rb@ ;
: fifo-cnt ( -- c ) fifo-flags rb@ h# 1f and ;
: data@ ( -- c ) begin fifo-cnt until fifo@ ;
: seq@ ( -- c ) sequence-step rb@ h# 7 and ;
: fifo! ( c -- ) fifo rb! ;
: cmd! ( c -- ) command rb! ;
: cnt! ( w -- ) wbsplit transfer-count-hi rb! transfer-count-lo rb! ;
: targ! ( c -- ) select/reconnect-bus-id rb! ;
: data! ( c -- ) begin fifo-cnt d# 16 < until fifo! ;
\ scsi chip noop and initialization
: scsi-nop ( -- ) nop cmd! ;
: init-scsi ( -- ) reset-chip cmd! scsi-nop ;
: wait-istat-clear ( -- error? )
d# 1000
begin
1 ms 1- ( count )
dup 0= ( count expired? )
istat@ ( count expired? istat )
0= or ( count clear? )
until ( count )
0= if
istat@ 0< if
cr ." Can't clear ESP interrupts: "
." Check SCSI Term. Power Fuse." cr
true exit
then
then
false
;
: clk-conv-factor ( -- n ) clock-frequency d# 5.000.000 / 7 and ;
\ initialize scsi chip, tune time amount, set async operation mode, and set scsi
\ bus id
: reset-my-scsi ( -- error? )
init-scsi
h# 93 select/reconnect-timeout rb!
0 sync-offset rb!
clk-conv-factor clock-conversion-factor rb!
h# 4 scsi-init-id 7 and or configuration rb!
wait-istat-clear
;
: reset-bus ( -- error? )
reset-scsi cmd! wait-istat-clear
;
: init-n-test ( -- ok? ) reset-my-scsi 0= ;
: get-buffers ( -- )
h# 8000 dma-alloc to mbuf0
/cmdbuf dma-alloc to cmdbuf
cmdbuf /cmdbuf false dma-map-in to cmdbuf-dma
;
: give-buffers ( -- )
mbuf0 h# 8000 dma-free -1 to mbuf0
cmdbuf cmdbuf-dma /cmdbuf dma-sync \ redundant
cmdbuf cmdbuf-dma /cmdbuf dma-map-out
cmdbuf /cmdbuf dma-free
-1 to cmdbuf -1 to cmdbuf-dma
;
: scsi-selftest ( -- fail? ) reset-my-scsi ;
\ dma-alloc and dma-map-in mbuf-dma
: mbuf-alloc ( -- )
/mbuf dma-alloc to mbuf
mbuf /mbuf false dma-map-in to mbuf-dma
;
\ dma-map-out and dma-free mbuf-dma
: mbuf-free ( -- )
mbuf mbuf-dma /mbuf dma-sync \ redundant
mbuf mbuf-dma /mbuf dma-map-out
mbuf /mbuf dma-free
-1 to mbuf
-1 to mbuf-dma
;
external
\ If any routine was using buffers allocated by dma-alloc, and was using dma mapped
\ by dma-map-in, it would have to dma-sync those buffers after making any changes to
\ them.
: open ( -- success? )
dma-open
" scsi-initiator-id" get-inherited-property 0= if
decode-int to scsi-init-id
2drop
map-scsi
init-n-test ( ok? )
dup if ( true )
get-buffers ( true )
else
unmap-scsi dma-close ( false )
then ( success? )
else
." Missing initiator id" cr false
dma-close
then ( success? )
;
: close ( -- )
give-buffers unmap-scsi dma-close
;
: reset ( -- )
dma-open map-scsi
h# 80 dma-breset
reset-my-scsi drop reset-bus drop
unmap-scsi dma-close
;
\ if scsi-selftest was actually using buffers allocated by mbuf-alloc, it would
\ have to do dma-sync after any changes to mbuf or mbuf-dma.
: selftest ( -- fail? )
map-scsi
mbuf-alloc
scsi-selftest
mbuf-free
unmap-scsi
;
new-device \ missing "reg" indicates a SCSI "wild-card" node
" sd" encode-string " name" property
finish-device
new-device \ missing "reg" indicates a SCSI "wild-card" node
" st" encode-string " name" property
finish-device
end0
-------------------------------------------------------------------------------------------
Code Example 3 Sample Driver for Bootable Devices
---------------------------------------------------------------------------------------------
\ sample fcode driver for bootable devices.
\ This driver supports "block" and "byte" type bootable devices, by using standard
\ "deblocker"and "disk-label" packages.
hex
headers
: copyright ( -- )
." Copyright 1992 - 1995 Sun Microsystems. All Rights Reserved" cr
;
h# 20.0000 constant scsi-offset
h# 40 constant /scsi
d# 25.000.000 constant clock-frequency
: identify-me ( -- )
" SUNW,my-scsi" encode-string " name" property
" scsi" device-type
my-address scsi-offset + my-space /scsi reg
;
identify-me
h# 10.0000 constant dma-offset
h# 10 constant /dma
-1 instance value dma-chip
external
: decode-unit ( addr len -- low high ) decode-2int ;
: dma-alloc ( size -- vaddr ) " dma-alloc" $call-parent ;
: dma-free ( vaddr size -- ) " dma-free" $call-parent ;
: dma-map-in ( vaddr size cache? -- devaddr ) " dma-map-in" $call-parent ;
: dma-map-out ( vaddr devaddr size -- ) " dma-map-out" $call-parent ;
\ Dma-sync could be dummy routine if parent device doesn't support.
: dma-sync ( virt-addr dev-addr size -- )
" dma-sync" my-parent ['] $call-method catch if
2drop 2drop 2drop
then
;
: map-in ( addr space size -- virt ) " map-in" $call-parent ;
: map-out ( virt size -- ) " map-out" $call-parent ;
headers
\ variables/values for sending commands, mapping etc.
-1 instance value scsi-init-id
-1 instance value scsi-chip
-1 instance value mbuf
-1 instance value mbuf-dma
h# 20 constant /mbuf
...
\ mapping and allocation routines for scsi
: map-scsi-chip ( -- )
my-address scsi-offset + my-space /scsi map-in to scsi-chip
;
: unmap-scsi-chip ( -- ) scsi-chip /scsi map-out -1 to scsi-chip ;
: map-scsi ( -- )
map-scsi-chip
\ allocate buffers etc. for "sense" command and status
...
;
: unmap-scsi ( -- )
\ free buffers etc. for "sense" command and status
...
unmap-scsi-chip
;
\ words related to scsi commands and register access.
...
: reset-my-scsi ( -- error? ) ... ;
: reset-bus ( -- error? ) ... ;
: init-n-test ( -- ok? ) ... ;
: get-buffers ( -- ) ... ;
: give-buffers ( -- ) ... ;
: scsi-selftest ( -- fail? ) ... ;
d# 512 constant ublock
0 instance value /block
0 instance value /tapeblock
instance variable fixed-len?
...
external
: set-timeout ( n -- ) ... ;
: send-diagnostic ( -- error? )
\ run diagnostics and return any error.
...
;
: device-present? ( lun target -- present? ) ... ;
: mode-sense ( -- true | block-size false ) ... ;
: read-capacity ( -- true | block-size false ) ... ;
\ Spin up a SCSI disk, coping with a possible wedged SCSI bus
: timed-spin ( target lun -- ) ... ;
: disk-r/w-blocks ( addr block# #blocks direction? -- #xfered )
... ( #xfered )
;
\ Execute "mode-sense" command. If failed, execute read-capacity command.
\ If this also failed, return d# 512 as the block size.
: disk-block-size ( -- n )
mode-sense if read-capacity if d# 512 then then
dup to /block
;
: tape-block-size ( -- n ) ... ;
: fixed-or-variable ( -- max-block fixed? ) ... ;
: tape-r/w-some ( addr block# #blks read? -- actual# error? ) ... ;
headers
: dma-open ( -- ) my-address dma-offset + my-space /dma map-in to dma-chip ;
: dma-close ( -- ) dma-chip /dma map-out -1 to dma-chip ;
\ After any changes to mbuf by cpu or any changes to mbuf-dma by device, synchronize
\ changes by issuing " mbuf mbuf-dma /mbuf dma-sync "
: mbuf-alloc ( -- )
/mbuf dma-alloc to mbuf
mbuf /mbuf false dma-map-in to mbuf-dma
;
\ dma-map-out and dma-free mbuf-dma
: mbuf-free ( -- )
mbuf mbuf-dma /mbuf dma-sync \ redundant
mbuf mbuf-dma /mbuf dma-map-out
mbuf /mbuf dma-free
-1 to mbuf
-1 to mbuf-dma
;
external
\ external methods for scsi bus ( "SUNW,my-scsi" node)
: open ( -- okay? )
dma-open
" scsi-initiator-id" get-inherited-property 0= if
decode-int to scsi-init-id
2drop
map-scsi
init-n-test ( ok? )
dup if ( true )
get-buffers ( true )
else
unmap-scsi dma-close ( false )
then ( success? )
else
." Missing initiator id" cr false
dma-close
then ( success? )
;
: close ( -- ) give-buffers unmap-scsi dma-close ;
: reset ( -- )
dma-open map-scsi
...
reset-my-scsi drop reset-bus drop
unmap-scsi dma-close
;
: selftest ( -- fail? )
map-scsi
mbuf-alloc
scsi-selftest
mbuf-free
unmap-scsi
;
headers
\ start of child block device
new-device \ missing "reg" indicates SCSI "wild-card" node
" sd" encode-string " name" property
" block" device-type
0 instance value offset-low
0 instance value offset-high
0 instance value label-package
\ The "disk-label" package interprets any partition information contained in
\ the disk label. The "load" method of the "block" device uses the load method
\ provided by "disk-label"
: init-label-package ( -- okay? )
0 to offset-high 0 to offset-low
my-args " disk-label" $open-package to label-package
label-package if
0 0 " offset" label-package $call-method
to offset-high to offset-low
true
else
." Can't open disk label package" cr false
then
;
0 instance value deblocker
: init-deblocker ( -- okay? )
" " " deblocker" $open-package to deblocker
deblocker if
true
else
." Can't open deblocker package" cr false
then
;
: device-present? ( lun target -- present? )
" device-present?" $call-parent
;
\ The following methods are needed for "block" device:
\ open, close, selftest, reset, read, write, load, seek, block-size,
\ max-transfer,read-blocks, write-blocks.
\ Carefully notice the relationship between the methods for the "block" device
\ and the methods pre-defined for "disk-label" and "deblocker"
external
\ external methods for "block" device ( "sd" node)
: spin-up ( -- ) my-unit " timed-spin" $call-parent ;
: open ( -- ok? )
my-unit device-present? 0= if false exit then
spin-up \ Start the disk if necessary
init-deblocker 0= if false exit then
init-label-package 0= if
deblocker close-package false exit
then
true
;
: close ( -- )
label-package close-package 0 to label-package
deblocker close-package 0 to deblocker
;
: selftest ( -- fail? )
my-unit device-present? if
" send-diagnostic" $call-parent ( fail? )
else
true ( error )
then
;
: reset ( -- ) ... ;
\ The "deblocker" package assists in the implementation of byte-oriented read and
\ write methods for disks and tapes. The deblocker provides a layer of buffering
\ to implement a high level byte-oriented interface "on top of" a low-level
\ block-oriented interface.
\ The "seek", "read" and "write" methods of this block device use corresponding
\ methods provided by "deblocker"
\ In order to be able to use the "deblocker" package this device has to define the
\ following four methods, which the deblocker uses as its low-level interface
\ to the device:
\ 1) block-size, 2) max-transfer, 3) read-blocks and 4) write-blocks
: block-size ( -- n ) " disk-block-size" $call-parent ;
: max-transfer ( -- n ) block-size h# 40 * ;
: read-blocks ( addr block# #blocks -- #read )
true " disk-r/w-blocks" $call-parent
;
: write-blocks ( addr block# #blocks -- #written )
false " disk-r/w-blocks" $call-parent
;
: dma-alloc ( #bytes -- vadr ) " dma-alloc" $call-parent ;
: dma-free ( vadr #bytes -- ) " dma-free" $call-parent ;
: seek ( offset.low offset.high -- okay? )
offset-low offset-high x+ " seek" deblocker $call-method
;
: read ( addr len -- actual-len ) " read" deblocker $call-method ;
: write ( addr len -- actual-len ) " write" deblocker $call-method ;
: load ( addr -- size ) " load" label-package $call-method ;
finish-device \ finishing "block" device "sd"
headers
\ start of child byte device
new-device \ missing "reg" indicates "wild-card" node
" st" encode-string " name" property
" byte" device-type
false instance value write-eof-mark?
instance variable file-mark?
true instance value scsi-tape-first-install
: scsi-tape-rewind ( -- [[xstatbuf] f-hw] error? ) ... ;
: write-eof ( -- [[xstatbuf] f-hw] error? ) ... ;
0 instance value deblocker
: init-deblocker ( -- okay? )
" " " deblocker" $open-package to deblocker
deblocker if
true
else
." Can't open deblocker package" cr false
then
;
: flush-deblocker ( -- )
deblocker close-package init-deblocker drop
;
: fixed-or-variable ( -- max-block fixed? )
" fixed-or-variable" $call-parent
;
: device-present? ( lun target -- present? )
" device-present?" $call-parent
;
\ The following methods are needed for "byte" devices:
\ open, close, selftest, reset, read, write, load, seek, block-size,
\ max-transfer, read-blocks, write-blocks. Carefully notice the relationship
\ between the methods for "byte" devices and the methods pre-defined for the
\ standard deblocker package.
external
\ external methods for "byte" device ( "st" node)
\ The "deblocker" package assists in the implementation of byte-oriented read
\ and write methods for disks and tapes. The deblocker provides a layer of
\ buffering to implement a high level byte-oriented interface "on top of" a
\ low-level block-oriented interface.
\ The "read" and "write" methods of this "byte" device use the corresponding
\ methods provided by the "deblocker"
\ In order to be able to use the "deblocker" package this device has to define the
\ following four methods which the deblocker uses as its low-level interface to
\ the device:
\ 1) block-size, 2) max-transfer, 3) read-blocks and 4) write-blocks
: block-size ( -- n ) " tape-block-size" $call-parent ;
: max-transfer ( -- n )
fixed-or-variable ( max-block fixed? )
if
\ Use the largest multiple of /tapeblock that to <= h# fe00
h# fe00 over / *
then
;
: read-blocks ( addr block# #blocks -- #read )
file-mark? @ 0= if
true " tape-r/w-some" $call-parent file-mark? ! ( #read )
else
3drop 0
then
;
: write-blocks ( addr block# #blocks -- #written )
false " tape-r/w-some" $call-parent file-mark? !
;
: dma-alloc ( #bytes -- vaddr ) " dma-alloc" $call-parent ;
: dma-free ( vaddr #bytes -- ) " dma-free" $call-parent ;
: open ( -- okay? ) \ open for tape
my-unit device-present? 0= if false exit then
scsi-tape-first-install if
scsi-tape-rewind if
." Can't rewind tape" cr
0= if drop then
false exit
then
false to scsi-tape-first-install
then
\ Set fixed-len? and /tapeblock
fixed-or-variable 2drop
init-deblocker 0= if false exit then
true
;
: close ( -- )
deblocker close-package 0 to deblocker
write-eof-mark? if
write-eof if
." Can't write EOF Marker."
0= if drop then
then
then
;
: reset ( -- ) ... ;
: selftest ( -- fail? )
my-unit device-present? if
" send-diagnostic" $call-parent ( fail? )
else
true ( error )
then
;
: read ( addr len -- actual-len ) " read" deblocker $call-method ;
: write ( addr len -- actual-len )
true to write-eof-mark?
" write" deblocker $call-method
;
: load ( addr -- size )
\ use my-args to get tape file-no
... ( addr file# )
\ position at requested file
...
dup begin ( start-addr next-addr )
dup max-transfer read ( start-addr next-addr #read )
dup 0 ( start-addr next-addr #read got-some? )
while ( start-addr next-addr #read )
+ ( start-addr next-addr' )
repeat ( start-addr end-addr 0 )
drop swap - ( size )
;
: seek ( byte# file# -- error? )
\ position at requested file
... ( byte# )
flush-deblocker ( byte# )
begin dup 0 while ( #remaining )
" mbuf0" $call-parent
over ublock min read ( #remaining #read )
dup 0= if ( #remaining 0 )
2drop true
exit ( error )
then ( #remaining #read )
- ( #remaining' )
repeat ( 0 )
drop false ( no-error )
;
finish-device \ finishing "byte" device "st"
end0
\ finishing "SUNW,my-scsi"
---------------------------------------------------------------------------------------------
