ValiDrive does the exact same thing, data-wise, to all USB storage that
it tests regardless of their size.
ValiDrive reads and writes ~8 KB per 576 locations, ( the graph is 36 x
16 blocks ) =
4,608 KB storage tested, +/- whatever ValiDrive's pre-test
'figures' it needs to overrun the drive's cache.
ValiDrive's routine is to
- read a block of original data,
- write a test pattern to that block,
- re-read and compare the test,
- re-write the original data,
- and then re-read and compare the original data
... ( a mini-SpinRide 6.1 Level 5 without DynaStat or repairs ).
For each of 576 blocks.
Even with those 5 data transfers, that's still only ~23,040 KB or
22.5 MB
data transfer.
That's one reason ValiDrive is so fast compared to tests that read and
write to every sector.
Even with their simpler one write and one read per cluster, those other
fake-drive tests still take way longer than ValiDrive.
- - - - -
So, what is the smallest USB storage device that ValiDrive can / will
test?
Would ValiDrive test a one-sector, one cluster
512 byte drive?
Bytes per
sector | Sectors per
cluster | Cluster
size | Number
of clusters | Drive size
in bytes | KB | MB |
| 512 | 1 | 512 | 1 | 512 bytes | 0.5 KB | 0.000488 MB |
| 512 | 1 | 512 | 576 | 294,912 bytes | 288 KB | 0.281250 MB |
| 512 | 4 | 2,048 | 1 | 2,048 bytes | 2 KB | 0.001953 MB |
| 512 | 4 | 2,048 | 576 | 1,179,648 bytes | 1,152 KB | 1.125 MB |
| 512 | 8 | 4,096 | 1 | 4,096 bytes | 4 KB | 0.003906 MB |
| 512 | 8 | 4,096 | 576 | 2,359,296 bytes | 2,304 KB | 2.25 MB |
| 512 | 8 | 4,096 | 1,152
( 2 clusters needed
to get 8 KB for each
of 576 test locations ) | 4,718,592 bytes | 4,608 KB | 4.5 MB |
I do not know if Validrvive would test a drive with fewer than 576
'pieces' and just test one or more of those pieces over and over,
meaning, ValiDrive might be able to test an
8 KB drive, just by
testing that one 8 KB 'block' 576 times.
A tiny drive with a 512-byte sector size and a 1 sector per cluster
would probably require 576 discrete addresses for Validrive to work,
where 512 bytes per cluster x 576 = 29,4912 bytes =
288 KB drive -
quite small, who'd waste their time faking one?
Most modern and worthy-of-being-faked drives would present a
typical 4KB cluster of 4,096 bytes, x 576 minimum size blocks for
Validrive = 2,359,296 bytes = 2,403 KB or a
2.25 MB drive - still a
small drive that presumably no one would offer as a fake.
If ValiDrive expects 576 blocks to be available, and expects to
transfer 8 KB ( 8,192 bytes ) per block, that's a drive size of a
minimum of 4,718,592 bytes or 4,608 KB or
4.5 MB drive - again, way
too small to expect folks to be faking them.
So what's the smallest USB drive anyone has to test, and let us know?
Maybe such information would reveal too much proprietary design
information about ValiDrive, empowering fakists to add
fool-the-ValiDrive programming, so we'll never 'know' or be told, we
can only discover by heuristically testing every tiny drive we can find.
Who can verify and confirm the smallest drive limit for ValiDrive 1?
@Steve ?
