In reply to a post by micksharpe:

...the good people at Burghfield.

I spent three months there on one project... my impression was that ROF(B) had a disarming tendency to go its own sweet way

In reply to a post by billford:

In reply to a post by micksharpe:

...the good people at Burghfield.

I spent three months there on one project... my impression was that ROF(B) had a disarming tendency to go its own sweet way

The guys in the Group certainly did when they got on their bicycles to go to the canteen.

In reply to a post by micksharpe:

The guys in the Group certainly did when they got on their bicycles to go to the canteen.

Yeah. I remember that- not a soul to be seen until the hooter went, then they popped out from all sorts of unlikely places

I had the use of a bicycle specially reserved for Honeywell Engineers, use of. It was an absolute death-trap. I'm amazed that I came away from that project with my goolies intact.

In reply to a post by micksharpe:

I'm not sure what you mean by "zeroed".

I think we are misunderstanding eachother here....
I mean zeroed as in zerored.... you have used a bootable utility on the PC to write zeroes to the entire disk.

In reply to a post by Pipexer:

I used to work for a mainframe manufacturer and we sometimes got requests from customers who had corrupted disks and no [recent] backups.

I appreciate that, but their data hasn't actually been fully overwritten in that respect.

In reply to a post by micksharpe:

On one occasion, I was sent a disk pack and was asked to check it out. It was mechanically sound but unreadable by the OS. I had access to engineering software that would pull data directly off the read heads. A lot of the data was OK but a good number of blocks had data shifted a few bits by a faulty drive controller. A lot of the corrupted blocks were directory entries which didn't help. I could have recovered 90% of the customer's data but when I quoted them for the work, they soon decided to re-key their data.

Again, in that example, the 1s and 0s were still on the surface. The data has not been secure erased or overwritten.

To clarify, I meant surface not in the technical term, as in, before they get sandblasted someone just nicks the drive.

Presumably the facility where they sandblasted the stuff was not just the office next door, even a different building? I'd at least expect every site to have a magnetic degauser or something similiar so that data can be pretty much securely erased without it going off site in some shape or form.

In reply to a post by Pipexer:

I mean zeroed as in zerored.... you have used a bootable utility on the PC to write zeroes to the entire disk.

I see what you mean. Successful data recovery is mostly a matter of good luck and data recovery companies are always cagey about what they can achieve. It may be possible to recover data that has been over-written once, or perhaps twice, but I doubt if data that has been overwritten multiple times can be recovered.

In any event, recovery of overwritten data is inherently error-prone and therefore of little use to commercial customers who inevitably want clean data for their money. However, even 10% readable data will be of interest to forensics and security specialists. You need to distinguish between commercial and forensic data recovery and recovery of deliberately overwritten data is definitely in the forensic category.

Edited by micksharpe (Thu 26-Apr-12 00:07:53)

In reply to a post by Pipexer:

To clarify, I meant surface not in the technical term, as in, before they get sandblasted someone just nicks the drive.

No disparagement intended, but you clearly haven't worked in a high-security establishment. I'm not saying it's impossible to nick one, but:

Every classified document (and in this context, digital storage media is a "document") is registered to a named (and security cleared) individual, is tracked whenever it's moved or transferred to someone else and subject to random checks at any time. It's also required to be locked away (in an appropriately approved secure cabinet) when you leave your office unattended, especially out of working hours but even while you go for a pee.

Get caught leaving a classified document out and unattended at any time and you've got yourself a severe problem.

This all applies right up to the moment when it's destroyed.

It's very much in the "owner's" interests not to lose it because, shortly after the next check, he'll quite likely be in jail, and for the same reason to keep it secure so that nobody else can nick it, because its loss will still be regarded as his responsibility. The Official Secrets Act is not one to be messed with.¹

Believe me, being a registered holder of classified documents is a right royal pita, which is why I avoided it as much as I could!

edit- forgot to mention: all employees (and their cars) were liable to searches on entry to and exit from the site, and if you were caught with a classified document on you...



¹Just for interest's sake, it's the only act (afaik) under which you can be punished twice for the same offence- once in the criminal court and again in the civil court.

Edited by billford (Thu 26-Apr-12 00:04:34)

There's definitely scope for making all documents handled by all ministers and civil servants classified then. That ought to stop those who leave things on trains, park benches etc.

/rolls eyes

Sure I once heard that a file has to be overwritten numerous times before it's "shadow" is finally completely unreadable...