4 ms·

Interesting, didn't even know you can cut files from a zip in that Windows zip file viewer. I would have thought it's some read-only filesystem like viewing a m

by Sol- 5y ago

Interesting, didn't even know you can cut files from a zip in that Windows zip file viewer. I would have thought it's some read-only filesystem like viewing a mounted CD or so. In that context I wonder if you could cut from rewritable CD-RWs as well back in the day (can't remember) - that seems like another abstraction that's similarly slow in reality.

jakub_g 5y ago
I never tried cutting from CD-RW, but AFAIR each burning would append a non-trivial header (like 20MBs or so) so that would be a pretty expensive thing to do :) AFAIR when you "copied" into CD-RW the files would show up semi-transparent (pending) and you'd have to click a button to process with burning. Probably same for cutting I guess.
- bluGill 5y ago
  Been years, but the ISO file system says 16 sectors past the start of the last track is where the file system index starts. (the first 15 sectors are reserved for booting) Then however many sectors you need for the index - which depends on how many files you have, and how long the filenames are. Note that both CDR and CDRW don't allow you to write sectors in the middle of a track, so you need to know where every file will be on disk before you can write anything - you can't build the index on the fly. (I remember this part because I was writing backups and so I didn't know how big the file would be until I was done and thus couldn't write the index first - I eventually got around the rule by creating a new track with just the index)
- TeMPOraL 5y ago
  Speaking of old Windows and CDs, Windows had some crazy trick to turn CD-R (not CD-RW) into rewriteable medium. I'm guessing they simulated a regular file system on top of an append-only representation. I never dug into the details back in the day, because I never used this feature. Unfortunately, IIRC, this trickery was enabled by default when copying files to CDs - which was a problem, because nothing else could read it. This caused me an unending stream of calls from friends and relatives, who all tried to burn some family/vacation photos onto a CD-R, in order to view them on their TVs, but the CD readers for TVs couldn't parse the format.
  - marcosdumay 5y ago
    Oh, the trick of placing the table of contents on the outtermost place of the written area, instead of the beginning of the CD. I think you were supposed to write a pointer at the original place, so the driver would know to look again, but outside in. Video CD players often didn't support that pointer. But actually, Windows was quite a latecomer on that feature. It's just that its UX was horrible so people would never know what option they choose, on other OSes (and other Windows software) people had to actually decide to use it.
  - ptman 5y ago
    UDF? https://en.wikipedia.org/wiki/Universal_Disk_Format https://en.wikipedia.org/wiki/Universal_Disk_Format
    - TeMPOraL 5y ago
      I think so. IIRC it was this: https://en.wikipedia.org/wiki/Live_File_System https://en.wikipedia.org/wiki/Live_File_System which is apparently the same thing as UDF.
  - grishka 5y ago
    I remember also another quirk — you could burn CDs that various appliances will read, and you could do it such that you're able to add more files later, but you had to do that through Windows Media Player.

by Sol- 5y ago

jakub_g 5y ago

I never tried cutting from CD-RW, but AFAIR each burning would append a non-trivial header (like 20MBs or so) so that would be a pretty expensive thing to do :) AFAIR when you "copied" into CD-RW the files would show up semi-transparent (pending) and you'd have to click a button to process with burning. Probably same for cutting I guess.

bluGill 5y ago
Been years, but the ISO file system says 16 sectors past the start of the last track is where the file system index starts. (the first 15 sectors are reserved for booting) Then however many sectors you need for the index - which depends on how many files you have, and how long the filenames are. Note that both CDR and CDRW don't allow you to write sectors in the middle of a track, so you need to know where every file will be on disk before you can write anything - you can't build the index on the fly. (I remember this part because I was writing backups and so I didn't know how big the file would be until I was done and thus couldn't write the index first - I eventually got around the rule by creating a new track with just the index)
TeMPOraL 5y ago
Speaking of old Windows and CDs, Windows had some crazy trick to turn CD-R (not CD-RW) into rewriteable medium. I'm guessing they simulated a regular file system on top of an append-only representation. I never dug into the details back in the day, because I never used this feature. Unfortunately, IIRC, this trickery was enabled by default when copying files to CDs - which was a problem, because nothing else could read it. This caused me an unending stream of calls from friends and relatives, who all tried to burn some family/vacation photos onto a CD-R, in order to view them on their TVs, but the CD readers for TVs couldn't parse the format.
- marcosdumay 5y ago
  Oh, the trick of placing the table of contents on the outtermost place of the written area, instead of the beginning of the CD. I think you were supposed to write a pointer at the original place, so the driver would know to look again, but outside in. Video CD players often didn't support that pointer. But actually, Windows was quite a latecomer on that feature. It's just that its UX was horrible so people would never know what option they choose, on other OSes (and other Windows software) people had to actually decide to use it.
- ptman 5y ago
  UDF? https://en.wikipedia.org/wiki/Universal_Disk_Format https://en.wikipedia.org/wiki/Universal_Disk_Format
  - TeMPOraL 5y ago
    I think so. IIRC it was this: https://en.wikipedia.org/wiki/Live_File_System https://en.wikipedia.org/wiki/Live_File_System which is apparently the same thing as UDF.
- grishka 5y ago
  I remember also another quirk — you could burn CDs that various appliances will read, and you could do it such that you're able to add more files later, but you had to do that through Windows Media Player.