I'll try to explain without confusing you any further, but if anything doesn't make sense, please let me know. The instructions on page 79 are contradictory, which doesn't help very much. The upper part of the page suggests you can create extra space on a DVD+RW disc by deleting titles, while the lower part, in the grey box, states you cannot. The bottom part is actually correct.
I'll split this into two sections - blank/unused and used discs then explore a few scenarios.
A DVD+RW is typically 4.7GB and will record approx. 2 hours
of video in SP
mode or 4 hours
mode. If you record more than one programme, they will appear consecutively in the disc editing menu, and shown as numbered blocks in the Title List. The last block shown will always be 'EMPTY',
but the actual size of this block can be all
of the total capacity of the disc.
If you insert a blank DVD+RW disc into the machine and view the title list, you will see this:
Although you can't 'record' to a block labelled EMPTY, this doesn't mean you cannot record to this disc. The blank
space on the disc precedes the block labelled as 'EMPTY'.
If you then record one programme of 1 hour duration in SP mode. the title list will look like this:
Once again, although you can't 'record' to the block labelled EMPTY, this doesn't mean this disc is full or that you cannot record anything else on it. The next programme recorder will appear between title 1 and the 'empty' block - as long as there is sufficient space on the disc remaining to record the programme.
If you then record a second programme of 1 hour duration in SP mode. the title list will look like this:
This disc is now full as 2 hours of video has been recorded in SP mode. However, if you'd only recorded 1 hour in total for these 2 programmes, you would still be able to record another hour of video in SP to this disc. The additional programmes would appear between the last numbered title and the 'empty' block - until the disc is full.
The empty block is always present and you cannot 'get rid of it', but it doesn't mean the disc is full or cannot be recorded on.
Hopefully, this goes some way to explaining it, but I still need need to explain what happens with used / full discs when you want to delete programmes and re-record.
There is a maximum length for messages posted on FixYa and I may be getting close to this, so rather than break off in mid-flow, I will continue the explanation for used discs in another message below this one. I will do this right now, but it will probably take me 20 minutes or so to write part 2, so keep checking back. It will be less confusing if you hold any questions until I've written part 2, but I will be happy to answer any after that.