Sky + disc space managment

If you hit Services on your Sky+ remote and then 5, it takes you to the disc managment menu. One of the options here concerns 'instant rewind' (how far back you can instantly rewind the channel you're watching). The option are 15min, 30min, 60min and Off. The way Sky+ works is a mystery to me, but can anyone tell me if turning 'instant rewind' to off will mean recordings take up less space on the hard drive?

I only ask because whenever I'm going away on holiday and my free space is running low, I never know if I'm going to have enough room to record the things I want. Logic tells me that if you have the 'instant rewind' enabled then it must be occupying space on the hard drive, and the longer you choose to be able to rewind the more space it takes.

I haven't confirmed this yet, but my theory is that if you have your Instant Rewind set to 30mins, and a two-hour film uses 4%, then the same film would use maybe 8% if you had your Instant Rewind set to 60mins. Conversely if you turned off your Instant Rewind, the film would only take 2%

Does any of that sound in the slightest bit logical?

The instant rewind feature if enabled records continuously on whatever channel you are watching. In other words if you have it set for 60 minutes than you can go back and review what's been on for the last 60 minutes at anytime.

Yes you are right when you say it take up space on the hard disk, but if you are recording a 90 minute film then it will not take up any extra space, as you are already recording it.

On average it takes 2% of the disks capacity to have the 60 minute feature enabled. But since it overwrites itself then it will never take anymore than that.

The instant rewind function on Sky + is used for when you want to record a program, lets say for example you are tuned to sky 1, box not in standby mode, and you switch on your tv and see a program you want to watch from the begining, press the record button, goto your planner and select the program, it should start from the begining of program, as long as you havent switch channels or switched over to that channel, it will record it for you.

If you switch channels or have the box in standby mode it won't work, the recording will only start from the time you went onto that channel.

I dont know if you have the HD version, but if you want to save some disk space, record the standard version while your on holiday, that will save some space.

Hope this helps.

Thanks for the answers, chaps. All you've both said I already knew (not that I'm not grateful ) but it does leave me a little puzzled. If the Instant Rewind feature makes no difference to how much space a recording takes up, why give users the various options?? For instance, what possible advantage can be gained by disabling the Instant Rewind feature, and if it makes no difference why would anyone choose to have it set to anything but the maxium 60 mins???