Read/write speed

Lowelei Posted messages 1 Status Membre -  
blux Posted messages 5003 Registration date   Status Modérateur Last intervention   -
Hello,
I am preparing for a "test" of knowledge in computer science and I can't quite understand how to determine which storage device is the fastest between
- a 2GB USB stick
- an external FireWire 2.0 drive
- a floppy disk

I obviously suspect that the floppy disk is the slowest, and that the USB stick can read/write information at a rate of 2GB/s (is that right?).
But what is FireWire 2.0? Is there any other terminology that qualifies a form of "speed"?
I apologize for the completely naive nature of my question, but when you're a noob, you're just a noob X))

So if you could shed some light on this (with relatively simple words :D), I would be really grateful!

4 réponses

blux Posted messages 5003 Registration date   Status Modérateur Last intervention   3 451
 
Hi,

the floppy disk is indeed the slowest.

As for the USB key, it depends on its interface: USB 2.0 or 3.0...
USB 2.0: 480 Mb/s
USB 3.0: over 4000 Mb/s

Firewire version 2 can go from 800 Mb/s to 3200 Mb/s

To get the speeds in bytes, you divide by 8... So, forget your key at 2 Go/s (what you mentioned is the key's capacity, not its speed)...

But all that, you can find online with two minutes of research...

--
See you later blux
 "People are crazy, they dare to do anything.
That's how you can recognize them"
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Qendac Posted messages 37 Status Membre
 
To not lose you right away, I clarify that Blux speaks in theoretical speed and I speak in practical speed, so both pieces of information are correct. However, can a 3.0 reach 4000 Mb/s theoretically? Seriously? Thanks for the info! I guess I'm not quite right then...
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MiniApp Posted messages 529 Registration date   Status Membre Last intervention   49
 
Hello,

The fastest peripheral in theory on your list is the USB flash drive.

In the order of the fastest hardware:

1-RAM (there are disks that store like a RAM stick).
2-Flash memory (USB drive, SSD)
3-Hard disk.

You also have to consider the speed (frequency) of the bus, for example: a hard disk has a frequency of 100Mb/s and a USB port has a frequency of 10Mb/s, in this case, the hard disk is faster, but in the vast majority of cases, the list I provided below represents reality.

Bus speeds:

1-RAM (Speeds from 1.6Gb/s to 24Gb/s)
2-USB (speed from 1.5Mb/s to 10Gb/s)
3-SATA (speed from 1.5Gb/s to 6Gb/s)
4-ATA/ATAPI (speed from 2.1Mo/s to 133Mo/s)

For FireWire, it's >here<.

Search and try: you will find the solution!
Snoop around and look everywhere: you will find knowledge!!
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blux Posted messages 5003 Registration date   Status Modérateur Last intervention   3 451
 
(there are disks that store like a RAM stick
Those, I don't know them, can you enlighten us?

You also have to take into account the speed (frequency) of the bus, for example: a hard drive has a frequency of 100Mb/s and a USB port has 10Mb/s
What you're giving us is a throughput, not a bus frequency.

Moreover, you confuse bits and bytes. For example, ATA is 133 Mo/s and not 133 Mb/s, which is a factor of 8 difference...

Thank you for not spreading inaccurate information.
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MiniApp Posted messages 529 Registration date   Status Membre Last intervention   49
 
Disks that store like RAM do exist (I am an amateur programmer and in the values to determine the type of disk there is DRIVE_RAMDISK). The throughput is related to the frequency (there can be a factor of difference). As for ATA/ATAPI, I apologize, I misread. I will modify.
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blux Posted messages 5003 Registration date   Status Modérateur Last intervention   3 451
 
There are disks that store like RAM (I'm an amateur programmer and in the values to determine the type of disk there is DRIVE_RAMDISK)
RAMDISK is an invention that uses RAM to present a pseudo-disk to the OS. We can't call it a reliable medium since as soon as the power is cut, the data disappears (information that a programmer who wants to store data permanently should know), unlike a USB drive, a hard disk (regardless of its interface or technology...) or a floppy disk.

The throughput is related to frequency (a difference factor may exist)
No, throughput is not solely related to frequency. In the SCSI interface, for example, regardless of the bus frequency, there is also the bus width: 8 bits or 16 bits. At the same frequency, a 16-bit wide bus will transfer twice as much data as an 8-bit bus in the same time.
The connection length also plays a role, along with several other factors...
This is valid for parallel protocols: SCSI, ATA...
For serial protocols: SATA, USB, IEEE-1394, the issue is different; frequency plays a role, but so do the information encoding processes (8b/10b-64b/66b, for example, for running disparity and clock synchronization...).

For ATA/ATAPI I apologize, I read it wrong. I will correct it.
For USB too, you made the mistake, for RAM as well...
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Qendac Posted messages 37 Status Membre
 
Hello!

In fact, the read/write speed is always specified in the product specifications. The USB key can be faster than the external hard drive, don't be mistaken! The 2GB of the key is actually the amount of data you can store on the key, not the speed.

USB 3.0 has a throughput (speed) of 60MB/s for reading/writing (as a general case) whereas Apple’s "FireWire 2.0" technology has a throughput of about 80MB/sec for the smallest model. So it is indeed faster.

Of course, this is "generally" speaking because on a case-by-case basis I think it is possible to have a USB key as fast or even faster than FireWire 2.0.

Just for informational purposes, there is also FireWire 2.0 that can go up to 320MB/sec and there it is definitely faster than any USB 3.0 key...
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