A bit of a break

Mmmm, holidays. A couple of opportunities came up in the diary and we grabbed them without hesitation.

First few days in the Netherlands, basically familiar territory with very little stress. This was the beach holiday, as we spent some time in Scheveningen (lovely beach near The Hague) and Katwijk aan Zee (also very nice beach; less tourist-y).

We also drove towards Vlissingen, taking in the remarkable bridges and flood barriers that keep the North Sea from flooding the low lands. The combined ‘Delta Works‘ are an audacious attempt to hold back the water (a constant battle as sea levels rise) and are generally considered one of the seven modern wonders of the world.

We travelled by car and the ever-reliable Stena ferry between Harwich and Hoek van Holland, choosing to ugrade to Captain Suite as it *was* a holiday 😉 – the overnight ferry means you can board around 9pm and be driving in Holland about 8am the next morning.

Can’t say I’ll opt for Captain’s Suite again. It is very nice but ships are large with plenty to do; the cabin is simply somewhere to sleep. I suspect they’re more sensible during daytime crossings where they can be better appreciated – still, we wanted to try!

The timing of our visit was to coincide with the Scheveningen International Firework festival. I swear when we booked everything this was scheduled to be on the Thursday, Friday and Saturday night which would’ve been every night of our visit. It seems they changed the schedule at some point to span two weekends, so we ended up missing half the fireworks – a real shame – but what we did see was still very good.

The second part of the break led us to France camping with some friends. We didn’t venture too far from Dunkirk (for various reasons) which meant the campsite was thoroughly British. Still, we managed to get out a bit and see some actual bits of France (and some of Belgium).

Now back to work, feeling somewhat refreshed.

When is a Copy not a Copy?

Xerox has received some likely unwelcome attention recently, with the discovery that their scanner-photocopiers are changing numbers under certain conditions.

The issue was highlighted by computer scientist David Kriesel, who discovered that figures in a scanned construction plan did not add up: in the original one room is listed as 21.11m³, in scans this number changed to 14.13m³. Other errors were also evident, with different tests yielding different errors.

Before & After scanning – David Kriesel

Blame appears to be apportioned to the compression method used when saving the scan. Dot-for-dot reproductions of pages are quite large files, so various techniques are used to reduce the file size needed.

It is suggested that if a document contains several similar-looking patterns on a page (such as a series of numbers) the scanner would record that both patterns are effectively the same and the reproduction would simply say ‘this patch is the same as that patch, so just duplicate it again here’ rather than recording both patches independently. If the quality is low enough, this might be incorrectly applied to two patches of a page which might look similar, when in fact they are slightly different.

Again, this is hypothetical and does not appear to have been solidly confirmed, but would indeed be a potential side-effect of compression and is consistent with the results seen.

Such errors might cause mere inconvenience, or they might lead to more substantial effects. Invoices and other financial documents could be subtly changed; doses of medical prescriptions modified, or incorrect construction plans leading to structural failure. One hopes that in many cases, trained practitioners might spot an error or question a seemingly erroneous value. After all, human errors (typos) are also likely to occur from time to time.

Nonetheless, this demonstrates a flaw in a system users would hope to place some degree of trust in: changing digits is not the expected behaviour of any reproduction system!

Xerox has issued their own statement, and are planning to release a patch shortly.