inability to back up old file on FAT not documented in the man page

[Wolfgang Kufner]

Binary package hint: zsync manpage

update: This bug is really just about the manpage. All the rest here is history.

zsync is a great tool. I am currently using it almost daily to get the iso updated to put on a stick from where I loopmount it with grub2.
I just tried to zsync directly onto a sticks FAT filesystem (can casper do only FAT?):

--------console copy "FAT"----------
wolfgang@karmic:/media/VERBAFAT/iso$ zsync http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso.zsync
#################### 100.0% 283.9 kBps DONE

reading seed file karmic-desktop-amd64.iso: ****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************Read karmic-desktop-amd64.iso. Target 100.0% complete.
verifying download...checksum matches OK
link: Operation not permitted
Unable to back up old file karmic-desktop-amd64.iso - completed download left in karmic-desktop-amd64.iso.part
used 728621056 local, fetched 0
--------end console copy "FAT"----------

I sat a while befor the stars started. That does not occur on harddisk. Here the same thing minutes later in a hd directory:

--------console copy "hd"----------
wolfgang@karmic:~/tmp$ zsync http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso.zsync
#################### 100.0% 369.5 kBps DONE

reading seed file karmic-desktop-amd64.iso: ****************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************Read karmic-desktop-amd64.iso. Target 88.5% complete.
downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
##################-- 93.0% 377.2 kBps

downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
###################- 96.3% 365.6 kBps

downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
#################### 100.0% 376.6 kBps DONE

verifying download...checksum matches OK
used 645783552 local, fetched 84755397
--------end console copy "hd"----------

Does zsync use links that are not available on FAT, making zsync on FAT impossible?
Should zsync be fixed/changed to do FAT also?
Otherwise this limitation/requirement should be stated on the man page of zsync, I think.
Or am I overlooking something?

[Wolfgang Kufner (wolfgangkufner)]

Doh, its working just as supposed now on FAT:
________
wolfgang@karmic:/media/VERBAFAT/iso$ zsync http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso.zsync
#################### 100.0% 189.8 kBps DONE

reading seed file karmic-desktop-amd64.iso: ********************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************************Read karmic-desktop-amd64.iso. Target 88.5% complete. *************************************************************************************
downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
##################-- 93.0% 518.2 kBps

downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
###################- 96.3% 409.3 kBps

downloading from http://cdimage.ubuntu.com/daily-live/current/karmic-desktop-amd64.iso:
#################### 100.0% 290.3 kBps DONE

verifying download...checksum matches OK
link: Operation not permitted
Unable to back up old file karmic-desktop-amd64.iso - completed download left in karmic-desktop-amd64.iso.part
used 645783552 local, fetched 84753175
_________

I guess I hit the server so soon it still had the old file. Even though I was sure I saw the new file on the web page. In combination with the "link: Operation not permitted" message it made me think something bigger was afoot.

All that is left is to put the inability to back up the old file on FAT into the man page. I think that would be a good idea.

zsync is really great :-)