Re: two tar issues: man page and --totals behaviour
On Fri, Jun 11, 2004 at 08:50:17AM -0400, Lowell Gilbert wrote:
Stefan A. Deutscher [EMAIL PROTECTED] writes:
Hi folks,
just noticed two issues with tar on FreeBSD 5.1 (actually, it is
GNU tar 1.13.25):
It's a heavily modified version of Gnu tar, actually.
(1) The man page is somewhat out of sync with what tar --help shows
in terms of options
Should I submit a PR for that one, or send a bug report to the gnu
tar maintainers, or both?
The man page isn't a primary documentation method; the *real* manual
is in Gnu info. [info tar] It's probably the local (FreeBSD)
changes that haven't gotten documented.
Ah, didn't think of info. Usually, man pages which have been abandoned
in favour of online info docs do say so. Will try to submit a patch for
that one, at least :-)
(2) The option --totals, according to the docs and --help, is supposed
to show the bytes _written_. It does not quite:
- When running plain 'tar c', it actually shows the bytes written.
- When running tar with any of the built-in compression flags, such
as 'tar -c -{z,Z,y}', it shows the exact same number of bytes as
when invoked without these flags.
While, technically, it might show the bytes written _to_ the
compression program, for all practical purposes it appears to show
what was _read_ from disk. The space used on tape may be
significantly smaller.
I understand that for backwards compatibility one cannot just change
the behaviour of this flag from one day to another. Fixing the docs
might be the easy way out, but I'd like to suggest the addition of
some flag that reports what was actually written _to_ the tape
device.
Even if the device-internal HW compression may change what actually
ends up on tape (i.e. compressing uncompressed stuff somewhat while
probably not gaining anything on gzip or bzip2), this would give a
better indicator of tape usage and space left on a tape.
This would be fairly tricky to implement with an external compression
filter in software, never mind in hardware.
Hm. I thought tar talk to the tape directly, even when it invokes an
external (or internal) compression algorithm? If it was to do something
like 'tar cf - . | gzip -dc - | dd if=- of=/dve/sa0' I'd understand that
counting what hits the tape _device_ from within tar is next to
impossible. However, I didn't see it do that. So, if tar talks to the
tape device directly and sends it blocks of (compressed) data, it
shouldn't be too hard to have it count 'em as well?
I have no idea whether this has been discussed here already, google
didn't like me enough to turn up relevant threads. Nor do I know how
the upcoming bsdtar handles that flag's behaviour.
I don't think bsdtar has such a flag, actually.
Again, should I submit a PR for that one, or send a bug report to
the gnu tar folks, or both?
If you have written the code to do what you're saying, please do
submit it.
Don't have any code to submit and didn't even look at the code yet. But
it does make a worthwhile project for one of those rainy evenings, I'll
put it on my to do list.
Cheers,
Stefan
___
[EMAIL PROTECTED] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: two tar issues: man page and --totals behaviour
Stefan A. Deutscher [EMAIL PROTECTED] writes:
Hi folks,
just noticed two issues with tar on FreeBSD 5.1 (actually, it is
GNU tar 1.13.25):
It's a heavily modified version of Gnu tar, actually.
(1) The man page is somewhat out of sync with what tar --help shows
in terms of options
Should I submit a PR for that one, or send a bug report to the gnu
tar maintainers, or both?
The man page isn't a primary documentation method; the *real* manual
is in Gnu info. [info tar] It's probably the local (FreeBSD)
changes that haven't gotten documented.
(2) The option --totals, according to the docs and --help, is supposed
to show the bytes _written_. It does not quite:
- When running plain 'tar c', it actually shows the bytes written.
- When running tar with any of the built-in compression flags, such
as 'tar -c -{z,Z,y}', it shows the exact same number of bytes as
when invoked without these flags.
While, technically, it might show the bytes written _to_ the
compression program, for all practical purposes it appears to show
what was _read_ from disk. The space used on tape may be
significantly smaller.
I understand that for backwards compatibility one cannot just change
the behaviour of this flag from one day to another. Fixing the docs
might be the easy way out, but I'd like to suggest the addition of
some flag that reports what was actually written _to_ the tape
device.
Even if the device-internal HW compression may change what actually
ends up on tape (i.e. compressing uncompressed stuff somewhat while
probably not gaining anything on gzip or bzip2), this would give a
better indicator of tape usage and space left on a tape.
This would be fairly tricky to implement with an external compression
filter in software, never mind in hardware.
I have no idea whether this has been discussed here already, google
didn't like me enough to turn up relevant threads. Nor do I know how
the upcoming bsdtar handles that flag's behaviour.
I don't think bsdtar has such a flag, actually.
Again, should I submit a PR for that one, or send a bug report to
the gnu tar folks, or both?
If you have written the code to do what you're saying, please do
submit it.
___
[EMAIL PROTECTED] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to [EMAIL PROTECTED]
two tar issues: man page and --totals behaviour
Hi folks,
just noticed two issues with tar on FreeBSD 5.1 (actually, it is
GNU tar 1.13.25):
(1) The man page is somewhat out of sync with what tar --help shows
in terms of options
Should I submit a PR for that one, or send a bug report to the gnu
tar maintainers, or both?
(2) The option --totals, according to the docs and --help, is supposed
to show the bytes _written_. It does not quite:
- When running plain 'tar c', it actually shows the bytes written.
- When running tar with any of the built-in compression flags, such
as 'tar -c -{z,Z,y}', it shows the exact same number of bytes as
when invoked without these flags.
While, technically, it might show the bytes written _to_ the
compression program, for all practical purposes it appears to show
what was _read_ from disk. The space used on tape may be
significantly smaller.
I understand that for backwards compatibility one cannot just change
the behaviour of this flag from one day to another. Fixing the docs
might be the easy way out, but I'd like to suggest the addition of
some flag that reports what was actually written _to_ the tape
device.
Even if the device-internal HW compression may change what actually
ends up on tape (i.e. compressing uncompressed stuff somewhat while
probably not gaining anything on gzip or bzip2), this would give a
better indicator of tape usage and space left on a tape.
I have no idea whether this has been discussed here already, google
didn't like me enough to turn up relevant threads. Nor do I know how
the upcoming bsdtar handles that flag's behaviour.
Again, should I submit a PR for that one, or send a bug report to
the gnu tar folks, or both?
Cheers,
Stefan
--
this space intentionally left blank
___
[EMAIL PROTECTED] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to [EMAIL PROTECTED]
