[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: Wheezy release: CDs are not big enough any more...

[Steve McIntyre]
> You're not measuring the time taken to sync to the flash drive
> either, so all you're going to be seeing is the speed of writing to
> cache.

Huh, I figured the 'sync' call at the end of each test run covered

> I've done lots of work with USB flash and MMC/SD cards over the last
> few years, and the best results are typically achieved using "dd
> bs=4M oflag=sync". That way, you'll normally get nicely-aligned date
> writes big enough to cover the internal flash page size and remove
> the horrendous effects of read-modify-write cycles.

Not noticeable in my test runs, so maybe I have an abnormal flash disk.
(The fact that it has a USB interface, rather than something closer to
the flash controller, probably makes a difference.)

Anyway, I've never been against people recommending things like
"dd bs=4M oflag=sync" when writing to disk media.  My pet peeve is when
people recommend "dd" but without any options other than if= and of=.
It is clear that many such people don't have a clue _why_ they use dd,
except an irrational, dare I say cargo-cult, aversion to cp with block

Reply to: