USB, SCSI, Firewire-What's fastest?

scsi
firewire
usb

in that order

USB 1.1 -- 1.2 megabytes per second
SCSI -- 5 megabytes per second
SCSI-2 -- 10 megabytes per second
UltraSCSI -- 20 megabytes per second
FireWire 400 -- 50 megabytes per second
USB 2.0 -- 60 megabytes per second

That said, a lot depends on the scanner. Most consumer scanners will not utilise the bandwidth of FireWire 400 or USB 2.0. A true optical 2400x2400 with 48 bit colour depth will, but it's still only momentary.

[sarcasm] Doesn't everybody know that ADB is still the fastest around?![/sarcasm] ADB runs at 12 kilobits/second, significantly slower than a modem!

USB 1.1 is 12 Mb/s (megabits per second).
USB 2.0 is 480 Mb/s
Some kinds of SCSI can go as high as "320 MByte/sec performance per channel," according to Adaptec. This is 3200 Mb/s.
FireWire 400 is 400 Mb/s, FireWire 800 is 800 Mb/s.

USB 2.0 seems to have the edge over Firewire. However, actual throughput is such that Firewire 400 is faster than USB 2.0, and Firewire 800 has them both beat. SCSI is cost prohibitive.

Using either USB 2.0 or FireWire will probably provide more than enough bandwidth to carry any scanner data.

So when did a byte consist of 10-bits? 320MB/s is 2560Mb/s. I wouldn't call SCSI cost prohibitive. Prices have come down quite a bit, FC on the other hand, that is cost prohibitive.

1 byte = 10 bits!! bit two much i guess

Yes, a byte consists of 8 bits (2^3), but I was under the impression that there was a start and stop bit on them, making it 10. I could be wrong.

KC9AIC said:

Yes, a byte consists of 8 bits (2^3), but I was under the impression that there was a start and stop bit on them, making it 10. I could be wrong.

Click to expand...

Start and stop bits are used on some serial protocols. SCSI is parallel, and Firewire as well as USB may not use start/stop bits.

In any case, Firweire 400 is usually faster than even USB 2.0. And as for a scanner, firewire is probably its fastest interface. Although as noted, SCSI does come in several speeds. You just have to know what speeds your devices support.

Remember that SCSI requires you to power-down to change peripherals, have a terminator, etc. Firewire is going to be your best bet here: connect the scanner, scan, disconnect.

A lot depends on the drivers, scanning software, and the chip inside the scanner.

While one interface may seem to have better specs, some of the companies can do things that really mess things up.

Of course there are also the bugs in the software and implementation of certain interfaces and features that can cause problems outside of scanning (ie, HPs all-in-one unit which has a sw app that slows the entire system down because it's polling the scan button way too often.)

So try them all and see which interface works best.

Albone said:

I got a Microtek 9800XL Scanner and I can use one of these three options to scan. I believe that I am limited to the speed of the scanner, so I can't maximize the full speed capacity of, say, firewire.

That being said, what would be the fastest and best method to scan, using OS 9.2?

Thanks!

Click to expand...

Scanning time really depends on your scaner, a parrell port would do you just fine. even an old serial port would probabley do the job.

That said any of the connections you listed will be more than cabable of doing what your asking.