[unix-history] / usr / man / man8 / rmt.8c

.TH RMT 8C "4 March 1983"
.UC 4
.SH NAME
rmt \- remote magtape protocol module
.SH SYNOPSIS
.B /etc/rmt
.SH DESCRIPTION
.I Rmt
is a program used by the remote dump and restore programs
in manipulating a magnetic tape drive through an interprocess
communication connection.
.I Rmt
is normally started up with an
.IR rexec (3X)
or
.IR rcmd (3X)
call.
.PP
The 
.I rmt
program accepts requests specific to the manipulation of
magnetic tapes, performs the commands, then responds with
a status indication.  All responses are in ASCII and in
one of two forms. 
Successful commands have responses of
.PP
.ti +0.5i
\fBA\fInumber\fR\en
.PP
where 
.I number
is an ASCII representation of a decimal number.
Unsuccessful commands are responded to with
.PP
.ti +0.5i
\fBE\fIerror-number\fR\en\fIerror-message\fR\en,
.PP
where
.I error-number
is one of the possible error
numbers described in
.IR intro (2)
and
.I error-message
is the corresponding error string as printed
from a call to
.IR perror (3).
The protocol is comprised of the
following commands (a space is present between each token).
.TP 15
.B O device mode
Open the specified 
.I device
using the indicated
.IR mode .
.I Device
is a full pathname and
.I mode
is an ASCII representation of a decimal
number suitable for passing to
.IR open (2).
If a device had already been opened, it is
closed before a new open is performed.
.TP 15
.B C device
Close the currently open device.  The
.I device
specified is ignored.
.TP 15
.B L whence offset
Perform an
.IR lseek (2)
operation using the specified parameters.
The response value is that returned from the
.I lseek
call.
.TP 15
.B W count
Write data onto the open device.
.I Rmt
reads
.I count
bytes from the connection, aborting if
a premature end-of-file is encountered.
The response value is that returned from
the
.IR write (2)
call.
.TP 15
.B R count
Read
.I count
bytes of data from the open device.
If
.I count
exceeds the size of the data buffer (10 kilobytes), it is
truncated to the data buffer size.
.I Rmt
then performs the requested 
.IR read (2)
and responds with 
\fBA\fIcount-read\fR\en if the read was
successful; otherwise an error in the
standard format is returned.  If the read
was successful, the data read is then sent.
.TP 15
.B I operation count 
Perform a MTIOCOP 
.IR ioctl (2)
command using the specified parameters.
The parameters are interpreted as the
ASCII representations of the decimal values
to place in the 
.I mt_op
and
.I mt_count
fields of the structure used in the
.I ioctl
call.  The return value is the
.I count
parameter when the operation is successful.
.TP 15
.B S
Return the status of the open device, as
obtained with a MTIOCGET 
.I ioctl
call.  If the operation was successful,
an ``ack'' is sent with the size of the
status buffer, then the status buffer is
sent (in binary).
.PP
Any other command causes 
.I rmt
to exit.
.SH DIAGNOSTICS
All responses are of the form described above.
.SH "SEE ALSO"
rcmd(3X),
rexec(3X),
mtio(4),
rdump(8C),
rrestore(8C)
.SH BUGS
People tempted to use this for a remote file access protocol
are discouraged.
Commit	Line	Data
01f7e3b2 C	1	.TH RMT 8C "4 March 1983"
	2	.UC 4
	3	.SH NAME
	4	rmt \- remote magtape protocol module
	5	.SH SYNOPSIS
	6	.B /etc/rmt
	7	.SH DESCRIPTION
	8	.I Rmt
	9	is a program used by the remote dump and restore programs
	10	in manipulating a magnetic tape drive through an interprocess
	11	communication connection.
	12	.I Rmt
	13	is normally started up with an
	14	.IR rexec (3X)
	15	or
	16	.IR rcmd (3X)
	17	call.
	18	.PP
	19	The
	20	.I rmt
	21	program accepts requests specific to the manipulation of
	22	magnetic tapes, performs the commands, then responds with
	23	a status indication. All responses are in ASCII and in
	24	one of two forms.
	25	Successful commands have responses of
	26	.PP
	27	.ti +0.5i
	28	\fBA\fInumber\fR\en
	29	.PP
	30	where
	31	.I number
	32	is an ASCII representation of a decimal number.
	33	Unsuccessful commands are responded to with
	34	.PP
	35	.ti +0.5i
	36	\fBE\fIerror-number\fR\en\fIerror-message\fR\en,
	37	.PP
	38	where
	39	.I error-number
	40	is one of the possible error
	41	numbers described in
	42	.IR intro (2)
	43	and
	44	.I error-message
	45	is the corresponding error string as printed
	46	from a call to
	47	.IR perror (3).
	48	The protocol is comprised of the
	49	following commands (a space is present between each token).
	50	.TP 15
	51	.B O device mode
	52	Open the specified
	53	.I device
	54	using the indicated
	55	.IR mode .
	56	.I Device
	57	is a full pathname and
	58	.I mode
	59	is an ASCII representation of a decimal
	60	number suitable for passing to
	61	.IR open (2).
	62	If a device had already been opened, it is
	63	closed before a new open is performed.
	64	.TP 15
65	.B C device
66	Close the currently open device. The
67	.I device
68	specified is ignored.
69	.TP 15
70	.B L whence offset
71	Perform an
72	.IR lseek (2)
73	operation using the specified parameters.
74	The response value is that returned from the
75	.I lseek
76	call.
77	.TP 15
78	.B W count
79	Write data onto the open device.
80	.I Rmt
81	reads
82	.I count
83	bytes from the connection, aborting if
84	a premature end-of-file is encountered.
85	The response value is that returned from
86	the
87	.IR write (2)
88	call.
89	.TP 15
90	.B R count
91	Read
92	.I count
93	bytes of data from the open device.
94	If
95	.I count
96	exceeds the size of the data buffer (10 kilobytes), it is
97	truncated to the data buffer size.
98	.I Rmt
99	then performs the requested
100	.IR read (2)
101	and responds with
102	\fBA\fIcount-read\fR\en if the read was
103	successful; otherwise an error in the
104	standard format is returned. If the read
105	was successful, the data read is then sent.
106	.TP 15
107	.B I operation count
108	Perform a MTIOCOP
109	.IR ioctl (2)
110	command using the specified parameters.
111	The parameters are interpreted as the
112	ASCII representations of the decimal values
113	to place in the
114	.I mt_op
115	and
116	.I mt_count
117	fields of the structure used in the
118	.I ioctl
119	call. The return value is the
120	.I count
121	parameter when the operation is successful.
122	.TP 15
123	.B S
124	Return the status of the open device, as
125	obtained with a MTIOCGET
126	.I ioctl
127	call. If the operation was successful,
128	an ``ack'' is sent with the size of the
129	status buffer, then the status buffer is
130	sent (in binary).
131	.PP
132	Any other command causes
133	.I rmt
134	to exit.
135	.SH DIAGNOSTICS
136	All responses are of the form described above.
137	.SH "SEE ALSO"
138	rcmd(3X),
139	rexec(3X),
140	mtio(4),
141	rdump(8C),
142	rrestore(8C)
143	.SH BUGS
144	People tempted to use this for a remote file access protocol
145	are discouraged.