Guest Eugene

3 Gb/sec or 300 MB/sec?

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Guest Eugene

Which do you prefer? SATA-IO's revised spec as well as SAS seem to be standardizing on the former more than the latter. Personally, I've preferred 300 MB/sec as it's directly comparable to the headroom specs of other interfaces. Manufacturers, however, seem to be standardizing on the first... either to emphasize the serial nature of their devices or (just as likely) because they think giga- sounds cooler than mega-. What's your opinion?

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What, no Fibre Channel specs, including the latest which is double the prior Gb/s ? :lol:

Maybe I'm having a mind fart this morning, but they are standardizing on 3Gb/s, instead of 300MB/s...huh? 3Gb/s = 3000Mb/8bits per byte= 375MB/s not 300MB/s ??? If so, then you need to make sure that is clear...375MB/s vs 300MB/s

SATA2 (or eSATA) I've seen 300MB/s, whereas plain 'ol SATA is 150MB/s, and I think you should make that distinction for the readers who may forget this fact.

Then we have USB2.0 at 480Mb/s, whereas FireWire (1394a?) 400 is well, 400Mb/s ;P , and FW800 is 800Mb/s, FW1600 1600Mb/s and so on. Yet all tests I've seen show the implementation of FW400 is in reality, giving greater maximum bandwidth than the slightly higher rating of 480MB/s for USB2.0.

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Well... I think the problem is, as always, that standards are good and that's why we have som many of them <_<

Right now we come from the different directions. One is the ATA/SCSI/Parallell world where speed has always been measured without controlbits and in bytes/s and the other is the Ethernet/Fibre channel/Serial world where performance is measured in "raw throughput" in bits/s.

I don't know and I (really) don't care which standard "wins" the only thing is confused people who don't know there are 10 bits in every "byte". I can foretell a number of arguments "You're stupid! 1500 Mbits/s is 187,5 Mbytes!" coming soon...

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Right now we come from the different directions. One is the ATA/SCSI/Parallell world where speed has always been measured without controlbits and in bytes/s and the other is the Ethernet/Fibre channel/Serial world where performance is measured in "raw throughput" in bits/s.

218369[/snapback]

Ethernet doesn't include the bits used in the wire encoding.

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What, no Fibre Channel specs, including the latest which is double the prior Gb/s:lol:

Maybe I'm having a mind fart this morning, but they are standardizing on 3Gb/s, instead of 300MB/s...huh? 3Gb/s = 3000Mb/8bits per byte= 375MB/s not 300MB/s ??? If so, then you need to make sure that is clear...375MB/s vs 300MB/s

SATA2 (or eSATA) I've seen 300MB/s, whereas plain 'ol SATA is 150MB/s, and I think you should make that distinction for the readers who may forget this fact.

Then we have USB2.0 at 480Mb/s, whereas FireWire (1394a?) 400 is well, 400Mb/s ;P , and FW800 is 800Mb/s, FW1600 1600Mb/s and so on. Yet all tests I've seen show the implementation of FW400 is in reality, giving greater maximum bandwidth than the slightly higher rating of 480MB/s for USB2.0.

218365[/snapback]

Keep in mind that serial protocols like SATA use 10b8b encoding so every byte transfered on the line consists of 10 bits, not 8. After decoding the channel can provide a hypothetical 300MB/s or 150MB/s transfer rate depending on the SATA generation used. The raw speed though is 3.0 Gb/s or 1.5Gb/s.

Free

Edited by freeborn

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As much as I would like to say "It's just marketing," the bits per second speed is correct since the interface is *serial* -- one bit follows the other.

I don't recall rating my RS-232 port in bytes / sec. :P

[Wow... maybe we should go back to baud... ]

I still think 3 Giga on a box will attract more attention that 300 Mega, especially when the Giga is emphasized as 'cool'.

Hmmm.... Gigacool . . .

DogEared

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300MB/s. It's directly comparable between other interfaces, but, more importantly, it's easier for less educated readers to understand.

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Well, 3 Gb/s is the amont of bits transfered over the wire in one second.

There is a 8bit/10bit encoding scheme that occured, so each byte become a 10 bit value transfered over the wire... which make the 3Gb/s become 300 MB/s.

as far as I recollect, a Data frame can be up to 8kB in SATA and 1 KBin SAS, separated with some words (word = 4 bytes) which effectively adds to the overhead lowering the transfer rate over a 1 second average...

...but like parallele SCSI at 320 MB/s, there is an overhead as well...

300 MB/s is therefore as relevent as 320 MB/s is for // SCSI, or 133MB/s for PATA...

Conclusion, it depends wether you're talking about the 'burst data xfer speed' versus cable data the tranfer rate.

As far as I know, nobody transfered 80 MB/s with ultra2 (SCSI LVD) on an ultra 2 controller and a 15kRPM latest generation SCSI drive capable of ~100MB/s sustained xfer speed...

MEJV

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as far as I recollect, a Data frame can be up to 8kB in SATA and 1 KBin SAS,

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Is that like '6 of one, half a dozen of the other'? :-p

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MB/s because when I think of transfer rates I usally relates that to some amount of data moved in one second or one minute (how long does it take to move 10GB or 100GB at that speed).

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I'm used to seeing it as 3 Gb/s and not 300 MB/s, but I switch between metric and English regularly at work so it's not a big deal for me to use two units. :D

Is it possible to use both, with the second one in parentheses? If you only use 300 MB/s, someone is bound to keep asking whether this is the same as the 3 Gb/s seen in advertising/boxes/other sites.

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I like the SATA/300 better. I consider it ackward that we have ATA/33, ATA/66, ATA/100, ATA/133, SATA/150 but SATA 3 Gbit/s.

If the 150 MB/s (or 1.5 Gbit/s) SATA wasn't usually referred as SATA/150 or SATA-150, it would probably be fine either way. But if "regular" SATA is 150, "SATA2" simply cannot be called 3 Gbit/s.

I'd favor SATA/150 and SATA/300 as these make sense even without the unit (MB/s or Gbit/s).

FIGHT!!!

"Judges, the ruling!"

SATA 3Gb/s = 219000

"Serial ATA" 3Gb/s = 121000

SATA "3 Gb/s" = 34500

"Serial ATA" "3 Gb/s" = 25500

SATA 3Gbit/s = 12700

"Serial ATA" 3Gbit/s = 1390

SATA "3 Gbit/s" = 10600

"Serial ATA" "3 Gbit/s" = 795

TOTAL = 425485

SATA 300 = 2740000

"Serial ATA" 300 = 2330000

TOTAL = 5070000 <-- "The winner, it's you!"

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What I say! "Judges, the ruling!" are be meaning "Judges , a ruling!"

We must are be having a game to smurf here.

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The question using bytes vs. bits to me is the standard... how useful is a bit versus a byte? Do you think in bytes or bits? What is your frame of reference. That is the question which we should all decide for ourselves. What is the metric by which we base our judgements... right now traffic is in b and files are in B generally... so I would say people are more comfortable with B... I would say b is better because it's the smallest denominator... but people will get used to any standard whatever is decided... the b vs. B has always existed... and probably will for a long time.

Is a foot a reasonable binary size? is a meter a reasonable binary size? but it comes down to what people are used to. Because we can always chop that up into a trillion x10^4 etc... or x10^-4 or whatever... .000001 or 100000

I see picture sizes :-/ 200kB 600kB 800kB so I think in bytes, so kB or GB or MB makes more sense... but someone who works with traffic is used to Mb/s would make more sense...

We're used to seeing everything in bytes because that's just how it's set up for us to see in M$ etc... everything is in bytes. But really we could think of it in bits just as easily. But we're used to bytes, so most people probably want bytes...

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The question using bytes vs. bits to me is the standard... how useful is a bit versus a byte? Do you think in bytes or bits? What is your frame of reference. That is the question which we should all decide for ourselves. What is the metric by which we base our judgements... right now traffic is in b and files are in B generally...

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Traffic is in bits?

I'm not using a single application that reports file transfer speeds in bits.

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Many measures of traffic are in bits - particularly in the traditional telecom space. The North American Digital Hierarchy uses bits / second - as in DS1 (1.544 megabits / second) and DS3 (44.736 megabits per second).

I am not arguing the SATA naming convention, just pointing out that some bandwith measurements are in bits / second.

Paul

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We're used to seeing everything in bytes because that's just how it's set up for us to see in M$ etc... everything is in bytes. But really we could think of it in bits just as easily. But we're used to bytes, so most people probably want bytes...

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Its human to cut down to the lowest common denominator. we say 2 dozen loafs of bread not 24, but either of those would be considered better then saying I have 4 half dozen loafs of bread. Bytes is a respected and oft used measurement for data sizes, even more so it size is exactly 8 bits, so as long as any bit size is devisible by 8 I think we should be using byte size, just like I consider 1024 bytes as a Kilobyte and 1024 Kilobytes a Megabyte. To go back to using bits makes me think that I should call my 400GB HD a 3,435,973,836,800 Bit Hard drive. (although I do understand that windows only sees them as 1024 blocks while Hd manufacturers see them 1000 blocks).

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You know there was a lawsuit over bytes vs. bits... the hard drive manufacturers got sued because they called a 40gig[abyte] hard drive, which really only contained 39,999,999 bits or something... hard drive manufacutrers lost. So again the metric of how large a file we work with is to me the most important deciding factor.

It's like science uses Metric, but cooking we use english...

Home computers use Bytes, Telecom uses bits...

it's like speaking 2 languages, I don't see either going away, it's not like the jpg/gif wars or anything...

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300MB - without question

Giga bits is intentionally misleading -- basically false (intentional lie) advertising for the general masses. What percent of the buying public knows the difference between b and B ????? 1% at best?

This really kills me. It is essentially equivalent to the ENRON debacle!

300MB/sec is absolutely wonderful. Why can't we be honest about it? Why must we effectively lie and say 3Gb ?????

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300MB - without question

Giga bits is intentionally misleading -- basically false (intentional lie) advertising for the general masses. What percent of the buying public knows the difference between b and B ?????  1% at best?

This really kills me. It is essentially equivalent to the ENRON debacle!

300MB/sec is absolutely wonderful. Why can't we be honest about it? Why must we effectively lie and say 3Gb ?????

218899[/snapback]

It *is* 3Gb...there's no lie there. It's the error checking bits that make it 300 MB/s rather than 375 MB/s.

Of course, in my humble opinion, the whole issue is sort of a non-issue, because no one will see the difference between 300 MB/s and 375 MB/s. Drives can't push it that hard, and are unlikely to be able to do so anytime soon. And of course, even if they could make that speed, one doubts that consumers would notice a difference. So to me, it's pretty much all a bunch of hooey. Might as well be 150 MB/s or 10,000 MB/s.

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