2 hardware questions

[Book]

1) Why isn't there any absolute measuring unit for the processing power of a cpu? For example, I once thought that Hz was such a unit, but newprocessors with lower Hz than the older ones are faster (have more processing power). Why isn't "FLOPS" used (like in the supercomputers) since it's probably more useful?

2) In what way are the SCSI HDDs different from the common ones (IDE, SATA, USB). I checked some of them at a local hardware shop and the only difference I see is that they have immense rotating speed (like 15000 RPM) but is it just that?

[Metalmurphy]

1) Correct me if im wrong but the Hz have to do with the Clock speed, some processors have newer tecnology that can do more stuff for each clock cycle, thats why they mesure it with FLOPS (floating point operations per second). I might be wrong on this though,


2) no idea

[Book]

1) OK, then why doesn't anybody adopt the FLOPS as a measuring unit?? No company mentions its processor's FLOPS.

[Hard core Rikki]

1 - It is commonly known the ARM cpu's of Apple were faster at performing tasks, using less clocks.

It is the industry who needs to adopt the FLOPS. Unless it does, expect people to rely on Ghz and chip maker's CPU's reputation.

The absence of referencing of the L2/L3 cache along with its value is also very misleading, for as long as Ghz is of leading usage. This will change with Conroe, as I see.

2 - SCSI is popular on high-performance workstations, servers, high-end peripherals, and in the consumer market by use of IEEE1394.
RAID arrays on servers almost always use SCSI hard disks.
Desktop computers and notebooks more typically use the ATA/IDE or the newer SATA interfaces for hard disks, and USB connections for external devices. Lower price. Isn't it what people want?

More on SCSI HERE

[Book]

1) OK, so the higher the FLOPS, the better the processor, no matter the architecture, cache, FSB, or the clock GHz?

2) So the SCSI refers to the type of connection that is used between the HDD and the Motherboard? And they work the SAME way, but they are just faster or something? Do I need a special motherboard to be able to use a SCSI HDD? Do they occupy more space/fit in the normal HDD slots of the computer case?

[KillerShots]

2. Generally, you will need a special PCI card (usually 64-bit for the performance, but 32-bit cards are available) to use SCSI-drives.

The interface has different advantages than IDE / SATA as well... for example, at the moment, you can fit 15 SCSI drives on a single cable (16 IDs total, with the controller occupying one ID).

The SCSI RAID card I use is generally available for $10, has a battery backup built in, and can control up to 45 drives (3 "channels").

In general, SCSI drives are much more expensive than IDE / SATA drives. On the other hand, a quick E-bay search tends to find large companies liquidating thousands of large SCSI drives for dirt cheap (for example, I picked up 5 180G SCA SCSI drives for $100). Picking up drives this way tends to have other risks as well... for example, my last batch of drives obtained this way (10 18G) had a block size of 516 bytes... which meant that no PC-based OS could use the drives (wonder what it was used for?). Luckily, I knew enough to change the block size back to 512 bytes (firmware re-write) and use them, but it is buyer beware out there.

[james.miller]

flops aren't the answer. floating point power isnt the only thing a cpu needs to be 'fast' and floating point ops arent the only type of instructions a cpu has to process. As such its still not an accurate measuremant of cpu power. It's better, but still not god enough.

I don't think there'll ever be a single unit we can measure by.

[dutchMasta]

1) i guess you could check benchmark comparisons, loads of sites have them, like xbitlabs and anandtech. cpus do so much and their architecture have advantages and disadvantages, so like...there wouldn't be one measurement of saying, for example, that cpu A is better at gaming but worse at divx encoding compared to cpu B (which I think was the case with amd and intel not so long ago?).

also, those articles give you a lot more information, like how quiet, how cool, overclockability, features, etc., so it's really the best way to know what you're buying. but...if you really don't have time, then i guess the one measure of how good a product is, though DAMN unreliable, is price.

2) scsi drivers are louder i think, too. other than that, most have been mentioned, better speeds, for servers, etc.

[Book]

2)

Generally, you will need a special PCI card (usually 64-bit for the performance, but 32-bit cards are available) to use SCSI-drives.

What do you mean a special PCI card? A MOBO that has PCI slots? I don't understand.

The interface has different advantages than IDE / SATA as well... for example, at the moment, you can fit 15 SCSI drives on a single cable

Again, I don't get what you're saying. How is it possible to fit 15 HDDs, each with its own cable slot, into one MOBO slot? If this is what you're saying (probably not).
SCSI drives are more expensive what do they offer anything special? I would be willing to spend more money on a faster, more reliable HDD, but again SCSI is just an interface. The HDD itself may not be that reliable or even fast. I also read that SCSI drives make much more noise and produce a lot of heat

What is the block size?

[KillerShots]

Originally Posted by Book

2)
What do you mean a special PCI card? A MOBO that has PCI slots? I don't understand.

No, I mean a special PCI card with SCSI connectors on the PCI card. Normally, high performance SCSI wants to use 64-bit PCI slots (PCI64, NOT PCI express)

Originally Posted by Book

Again, I don't get what you're saying. How is it possible to fit 15 HDDs, each with its own cable slot, into one MOBO slot? If this is what you're saying (probably not).

No, you can fit 15 hard drives on one cable with Ultra SCSI (7 with the previous standard). Each hard drive gets an address, anywhere from 0 - 15 (though the card usually occupies 15).

Originally Posted by Book

SCSI drives are more expensive what do they offer anything special? I would be willing to spend more money on a faster, more reliable HDD, but again SCSI is just an interface. The HDD itself may not be that reliable or even fast. I also read that SCSI drives make much more noise and produce a lot of heat

The main advantage SCSI has nowadays over other interfaces is quantity - like I said, you get 15 drives per interface. With SATA, you get 1 drive per interface. With IDE, you get 2 (with lowered performance).

Most of the time, they tend to be slightly more reliable than other hard drives, but they're not infallable. Noise / heat - depends on the vendor. I can't hear mine at all once they spin up, though with the way I have them packed I really should get some fans in there to dissipate the heat.

Originally Posted by Book

What is the block size?

It's something you really shouldn't need to worry about when dealing with PCs - it should always be 512. If it's not, no PC operating system will have a clue what to do with it.

[ChrisRay]

FLOPS themselves can be innacurate as well. Because of how they can be misintepreted or misrepresented. For example with graphic hardware you can measure FLOPS in overall rendering capability,

Pixel throughput, Vertex throughput, texel throughput, Or math capabilities. And theres no "proper" way of measuring this.

[Book]

No, I mean a special PCI card with SCSI connectors on the PCI card. Normally, high performance SCSI wants to use 64-bit PCI slots (PCI64, NOT PCI express)

OK, so no motherboard has SCSI slots on itself (like in IDE, they do have slots for the IDE cables so you don't need a PCI card)? Could I buy a motherboard with SCSI slots on it?

The main advantage SCSI has nowadays over other interfaces is quantity - like I said, you get 15 drives per interface. With SATA, you get 1 drive per interface. With IDE, you get 2 (with lowered performance).

I've only used IDE cables and can understand why you say I can fit 2 HDDs with 1 cable, the calble itself has 2 interfaces to connect with, and 1 that fits to the MOBO. Is it the same case with SCSI cables (16 overall cable slots?)? and why do IDE HDDs work at lower performance?

[KillerShots]

It's possible to get a motherboard with SCSI built in... but it's not common. Personally, I'd recommend if you really want SCSI, you get a SCSI card rather than a mobo in case you ever upgrade. That way you don't have to ever look for a mobo that specifically supports SCSI later on.

I think you understand that there's up to 16 connectors on a SCSI cable, but I just want to be clear that there tends to be only one connector on the mobo or PCI card. You can get multiple "channels" (channels are connectors, essentially), but you certainly never have 16 connectors on the board .

IDE hard drives can take full advantage of ATA-100 or better if (and only if) there's only one device on the cable. I'm sure someone else could explain that better than I could - I'll have to admit that I've pretty much taken it for granted.

[james.miller]

Originally Posted by KillerShots

IDE hard drives can take full advantage of ATA-100 or better if (and only if) there's only one device on the cable. I'm sure someone else could explain that better than I could - I'll have to admit that I've pretty much taken it for granted.

no, that hasnt been the case for years