Where has the disk space gone?

[Nick]

Just a mad thought. You have emptied the recycle bin?

[Mark Hennessy]

WinDirStat was Nick's suggestion; I suggested SequoiaView. Although it probably won't tell you anything that you don't already know.

Personally I would go along with the idea to copy everything over to another drive.

Separate question, but regarding all these backups, it's good that you're doing them, but have you tried restoring from them? I ask because I've had to help people who say "it's all OK - it backs up once a week", but in practice the backups are useless (for example, just system backups, no data). In short, backups you can't use are worse than no backups because of the false confidence they offer.

[Radio Fixer]

Thanks Mark, sorry to get Progs confused but no matter.

I may, as soon as I have time, backup to another drive and format the original.

As to trying the W7 backup system I have tried it and it has worked. But Yes! a good idea to do it now and again. Everything of importance I just copy across manually so that is pretty safe.

What you are suggesting is the same as having a camera security system: every so often you need to look back and make sure it is recording.

thanks Gary

[Radio Fixer]

Hi Nick

I deleted the ~Recycle Bin on the backup drive (that was 17GB) and that didn't make much difference. On the C: drive there is 3.9GB in the BIN, so not much but its time for an empty.

thanks Gary

[Refugee]

Just a thought.
Before you do a backup write down the dates of the two oldest backup files and then run backup.
Now check the date of the oldest backup file and see if it was once the second oldest backup file. It should dump the oldest one in order to make space for the new one.
If this is true then the backup files will be wiped starting with the oldest first leaving the most recent one if you fill the backup drive with some other unrelated files completely leaving only the newest backup file before disk full shows.
Also adding a copy of a folder larger than the remaining space will prove this by deleting the oldest backup file.
Modern computers tend to do this to help prevent fragmented drives and to use the full area of the physical disk inside the drive to even out wear of the surface.

[Nick]

Modern computers tend to do this to help prevent fragmented drives and to use the full area of the physical disk inside the drive to even out wear of the surface.

"Modern computers"? - hard drives have no surface wear at all - the head flies above the surface - it never touches (bad things happen if it does). If anything, most operating systems try to keep data physically close on hard drives to reduce inter-track movement by the heads - rotations latency depends only on the RPM of the disk and that is fixed - by positioning data close together, inter-track movement of the heads is minimised and data transfer rates can be maintained. Head movement is one of the few things within the control of the o/s.

Hard drives do not do wear levelling and never have - solid state drives (SSDs) use sophisticated algorithms to distribute data depending on how often its used and how many times the underlying cells have been written - modern SSDs also contain cells with differing capabilities - specifically speed and number of supported writes. The drives also contain a lot of "spare" sectors that are seamlessly mapped in when an in-use sector is unusable due to excessive number of writes or other failure modes.

FWIW, the external view of the sectors of an SSD is a fabrication of the SSD's memory management subsystem and will bear no relationship at all to the physical utilisation of memory within the device.

[Refugee]

I was thinking of general mechanical wear of the physical parts in general as opposed to the actual surface. Old hard drives in 386 machines used to rattle during boot up as they got old for this reason. A lot of water has gone under the bridge since then.
It is just good practice to keep old files while disk space is there so that the undelete function works and goes further back.

[Radio Fixer]

Tried deleting (after copying a folder and subfolders to another external drive) 75 mB of data from the C drive. I can happily report that W7 backup system restored it faultlessly from the normal backup external drive and was very easy to use.

Gary

[Nick]

Last thought on this - its possible, with all the deletes going on, that your external disk has filled with restore points and file versions.

before you initialise it, just go to Control Panel->System Protection

If, under Available Drives, your external drive is listed, click on the drive entry then Configure.

In the Restore Settings section, select Turn off system protection.

Under Disk space usage, then select the Delete button to remove all restore points and old file versions on that drive.

Then press OK.

I suspect that will have an serious impact!

[Radio Fixer]

You were on the right track there Nick, loads of old Backups.

Path for W7 was:  Control Panel > System Security > Backup and Restore > Manage Space. Which brings up a window with a View Backups button. Hit that and you get to see all the old backups going back years.

   

Delete all the old and Hey! Presto disk space is back again.

 So it shows, as you have said before, Format is the unsubtle way and you don't find out what the problem was for the future.

   

thanks Gary