Note that this is not all writing of optical media, much less reading of optical media, but specifically packet writing, a comparatively rarely-used set of functionality to provide the appearance of limited modifiability on write-once media.
Packet writing allows users to create, modify, and delete files and directories on demand without the need to burn a whole disc. Packet writing technology achieves this by writing data in incremental blocks rather than in a single block.
Deleting files and directories of a CD-R using packet writing technology does not recover the space occupied by these objects but, rather, they are simply marked as being deleted (making them effectively hidden). Similarly, changes to files cause new instances to be created instead of replacing the original files. Because of this, the available space on a non-rewritable medium using packet writing technology will decrease every time its content is modified.
I’ve burned many optical media discs, but never made use of packet writing.
EDIT: I think that wodim is probably the most-commonly-used optical media burning software for data discs on Linux, and looking at its man page, it apparently never got packet writing support out of being flagged experimental, for perspective:
-packet
Set Packet writing mode. This is an experimental interface.
pktsize=#
Set the packet size to #, forces fixed packet mode. This is an experimental interface.
-noclose
Do not close the current track, useful only when in packet writing mode. This is an experimental interface.
I’ve burned many optical media discs, but never made use of packet writing.
Its old magic. Back when CD-R media was expensive ($20 USD per disc) “closing the disc” meant never writing to the disc again. If you only put a few megabytes on the disc might mean wasting a lot of money. Instead you could “close the session” which would cost you some capacity on the disc but let you write more to it in the future. Sometimes you would want to write the same filename (but a revised file) to the disc later, but because the file was already there, you’d need to “delete” the original before writing the new version. I think this is where this packet writing mode would come into play.
Within a few years Re-writable CD-R (CDR-W) came out and most of this wasn’t needed anymore. You could wipe the whole disc and start fresh.
I was under the impression this was all optical disc writing.
When the family got a computer with a CD-RW drive in 1999, I used a CD-RW disc as a sort of portable USB, I guessing that was the last time when I used packet writing. :)
I used packet writing for a while when I got my first DVD-RW drive. A few years later, multi gigabyte flash drives became affordable and there was no need to mess with DVD-RWs anymore.
Note that this is not all writing of optical media, much less reading of optical media, but specifically packet writing, a comparatively rarely-used set of functionality to provide the appearance of limited modifiability on write-once media.
https://en.wikipedia.org/wiki/Packet_writing
I’ve burned many optical media discs, but never made use of packet writing.
EDIT: I think that
wodimis probably the most-commonly-used optical media burning software for data discs on Linux, and looking at its man page, it apparently never got packet writing support out of being flagged experimental, for perspective:Its old magic. Back when CD-R media was expensive ($20 USD per disc) “closing the disc” meant never writing to the disc again. If you only put a few megabytes on the disc might mean wasting a lot of money. Instead you could “close the session” which would cost you some capacity on the disc but let you write more to it in the future. Sometimes you would want to write the same filename (but a revised file) to the disc later, but because the file was already there, you’d need to “delete” the original before writing the new version. I think this is where this packet writing mode would come into play.
Within a few years Re-writable CD-R (CDR-W) came out and most of this wasn’t needed anymore. You could wipe the whole disc and start fresh.
Thanks for the clarification!
I was under the impression this was all optical disc writing.
When the family got a computer with a CD-RW drive in 1999, I used a CD-RW disc as a sort of portable USB, I guessing that was the last time when I used packet writing. :)
I used packet writing for a while when I got my first DVD-RW drive. A few years later, multi gigabyte flash drives became affordable and there was no need to mess with DVD-RWs anymore.