{"id":3554,"date":"2022-12-20T17:09:00","date_gmt":"2022-12-20T20:09:00","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/rmt-man8\/"},"modified":"2022-12-20T17:09:00","modified_gmt":"2022-12-20T20:09:00","slug":"rmt-man8","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/rmt-man8\/","title":{"rendered":"RMT (man8)"},"content":{"rendered":"

RMT<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
DIAGNOSTICS<\/a>
SEE ALSO<\/a>
BUGS<\/a>
AUTHOR<\/a>
AVAILABILITY<\/a>
HISTORY<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

rmt \u2212 remote magtape protocol module<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

rmt<\/b><\/p>\n

DESCRIPTION <\/a> <\/h2>\n

Rmt<\/b> is a program used by the remote dump<\/b>(8), restore<\/b>(8) or tar<\/b>(1) programs in manipulating a magnetic tape drive through an interprocess communication connection. Rmt<\/b> is normally started up with an rexec<\/b>(3) or rcmd<\/b>(3) call.<\/p>\n

The rmt<\/b> program accepts requests specific to the manipulation of magnetic tapes, performs the commands, then responds with a status indication. All responses are in ASCII<\/b> and in one of the following two forms.<\/p>\n

Successful commands have responses of:<\/p>\n

A<\/b>number<\/i>n<\/p>\n

where number<\/i> is an ASCII<\/b> representation of a decimal number.<\/p>\n

Unsuccessful commands are responded to with:<\/p>\n

E<\/b>error-number<\/i>nerror-message<\/i>n<\/p>\n

where error-number<\/i> is one of the possible error numbers described in intro<\/b>(2) and error-message<\/i> is the corresponding error string as printed from a call to perror<\/b>(3).<\/p>\n

The protocol is comprised of the following commands, which are sent as indicated – no spaces are supplied between the command and its arguments, or between its arguments, and n indicates that a newline should be supplied:
O<\/b>device<\/i>nmode<\/i>n<\/p>\n

Open the specified device<\/i> using the indicated mode<\/i>. Device<\/i> is a full pathname and mode<\/i> is an ASCII<\/b> representation of a decimal number suitable for passing to open<\/b>(2). If a device had already been opened, it is closed before a new open is performed.<\/p>\n

C<\/b>device<\/i>n<\/p>\n

Close the currently open device. The device<\/i> specified is ignored.<\/p>\n

L<\/b>whence<\/i>noffset<\/i>n<\/p>\n

Perform an lseek<\/b>(2) operation using the specified parameters. The response value is that returned from the lseek<\/b> call.<\/p>\n

W<\/b>count<\/i>n<\/p>\n

Write data onto the open device. Rmt<\/b> reads count<\/i> bytes from the connection, aborting if a premature end-of-file is encountered. The response value is that returned from the write<\/b>(2) call.<\/p>\n

R<\/b>count<\/i>n<\/p>\n

Read count<\/i> bytes of data from the open device. If count<\/i> exceeds the size of the data buffer (10 kilobytes), it is truncated to the data buffer size. Rmt<\/b> then performs the requested read<\/b>(2) and responds with A<\/b>count-read<\/i>n 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.<\/p>\n

I<\/b>operation<\/i>ncount<\/i>n<\/p>\n

Perform a MTIOCOP ioctl<\/b>(2) command using the specified parameters. The parameters are interpreted as the ASCII<\/b> representations of the decimal values to place in the mt_op<\/b> and mt_count<\/b> fields of the structure used in the ioctl<\/b> call. The return value is the count<\/i> parameter when the operation is successful.<\/p>\n

By issuing the I-1n0n<\/b> command, a client will specify that he is using the VERSION 1 protocol.<\/p>\n

For a VERSION 0 client, the operation<\/i> parameter is the platform mt_op<\/b> value (could be different if the client and the rmt<\/b> server are on two different platforms). For a VERSION 1 client, the operation<\/i> parameter is standardized as below:<\/p>\n\n\n\n\n\n\n\n\n\n
<\/td>\n\n

0<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTWEOF<\/b> command (write count<\/i> end-of-file records).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

1<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTFSF<\/b> command (forward space over count<\/i> file marks).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

2<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTBSF<\/b> command (backward space over count<\/i> file marks).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

3<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTFSR<\/b> command (forward space count<\/i> inter-record gaps).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

4<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTBSR<\/b> command (backward space count<\/i> inter-record gaps).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

5<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTREW<\/b> command (rewind).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

6<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTOFFL<\/b> command (rewind and put the drive offline).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

7<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTNOP<\/b> command (no operation, set status only).<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

i<\/b>operation<\/i>ncount<\/i>n<\/p>\n

Perform an extended MTIOCOP ioctl<\/b>(2) command using the specified parameters. The parameters are interpreted as the ASCII<\/b> representations of the decimal values to place in the mt_op<\/b> and mt_count<\/b> fields of the structure used in the ioctl<\/b> call. The return value is the count<\/i> parameter when the operation is successful. The possible operations are:<\/p>\n\n\n\n\n\n\n\n\n
<\/td>\n\n

0<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTCACHE<\/b> command (switch cache on).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

1<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTNOCACHE<\/b> command (switch cache off).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

2<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTRETEN<\/b> command (retension the tape).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

3<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTERASE<\/b> command (erase the entire tape).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

4<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTEOM<\/b> command (position to end of media).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

5<\/b><\/p>\n<\/td>\n

<\/td>\n\n

Issue a MTNBSF<\/b> command (backward space count files to BOF).<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

S<\/b><\/p>\n<\/td>\n

<\/td>\n <\/td>\n<\/tr>\n<\/table>\n

Return the status of the open device, as obtained with a MTIOCGET ioctl<\/b> call. If the operation was successful, an \u201cack\u201d is sent with the size of the status buffer, then the status buffer is sent (in binary, which is non-portable between different platforms).<\/p>\n

s<\/b>sub-command<\/i><\/p>\n

This is a replacement for the previous S<\/b> command, portable across different platforms. If the open device is a magnetic tape, return members of the magnetic tape status structure, as obtained with a MTIOCGET<\/b> ioctl call. If the open device is not a magnetic tape, an error is returned. If the MTIOCGET<\/b> operation was successful, the numerical value of the structure member is returned in decimal. The following sub commands are supported:<\/p>\n\n\n\n\n\n\n\n\n\n
<\/td>\n\n

T<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_type<\/b> which contains the type of the magnetic tape device.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

D<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_dsreg<\/b> which contains the “drive status register”.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

E<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_erreg<\/b> which contains the “error register”. This structure member must be retrieved first because it is cleared after each MTIOCGET<\/b> ioctl call.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

R<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_resid<\/b> which contains the residual count of the last I\/O.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

F<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_fileno<\/b> which contains the file number of the current tape position.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

B<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_blkno<\/b> which contains the block number of the current tape position.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

f<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_flags<\/b> which contains MTF_ flags from the driver.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

b<\/b><\/p>\n<\/td>\n

<\/td>\n\n

return the content of the structure member mt_bf<\/b> which contains the optimum blocking factor.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

Any other command causes rmt<\/b> to exit.<\/p>\n

DIAGNOSTICS <\/a> <\/h2>\n

All responses are of the form described above.<\/p>\n

SEE ALSO <\/a> <\/h2>\n

rcmd<\/b>(3), rexec<\/b>(3), \/usr\/include\/sys\/mtio.h,<\/i> rdump<\/b>(8), rrestore<\/b>(8)<\/p>\n

BUGS <\/a> <\/h2>\n

People should be discouraged from using this for a remote file access protocol.<\/p>\n

AUTHOR <\/a> <\/h2>\n

The dump\/restore<\/b> backup suit was ported to Linux\u2019s Second Extended File System by Remy Card . He maintained the initial versions of dump<\/b> (up and including 0.4b4, released in january 1997).<\/p>\n

Starting with 0.4b5, the new maintainer is Stelian Pop .<\/p>\n

AVAILABILITY <\/a> <\/h2>\n

The dump\/restore<\/b> backup suit is available from <\/p>\n

HISTORY <\/a> <\/h2>\n

The rmt<\/b> command appeared in 4.2BSD.<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

rmt \u2212 remote magtape protocol module <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[5,52,4,674],"class_list":["post-3554","post","type-post","status-publish","format-standard","hentry","category-8-administracion-del-sistema","tag-5","tag-administracion","tag-man8","tag-rmt"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3554","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=3554"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/3554\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=3554"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=3554"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=3554"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}