Today we are going to take a closer look at the first SerialATA hard disk drive, which has already started selling: this is Seagate Barracuda ATA V. Seagate Company appeared a kind of a pioneer in pushing forward the new interface and seems to have really serious intentions. Our goal will be to check how well SerialATA interface works and to compare the performance of SATA and ATA hard disk drives to find out if the game was worth the candle.
Closer Look: Serial ATA
So, what is SerialATA? This is a new interface, which should replace the common ATA interface. The major difference between them is a different way of transferring data along the cable. Instead of the parallel 40-pin cable the new interface uses only two conductor pairs plaited together with three earthing conductors making a flat cable. Each conductor pair can transfer the data in their own direction. The data transfer principle is absolutely the same as the one used in Ethernet or FibreChannel (only the operation frequency is different). With this data transfer procedure the interface ensures 1.5Gbit/sec rate at up to 1m distance.
Well, we will not continue with the small talk any more, let’s just answer one question: who needs SerialATA? We will try to recall all parties interested, and we will begin with the hard disk drive manufacturers. Do they really need the new interface? At present, I can hardly find any powerful arguments in favor of the urgent introduction of the new interface.
It’s true, ATA/ATAPI6 standard managed to solve the big drives problem (namely it allowed the drives to overcome the notorious 128GB barrier), and if some of the manufacturers believe that their drives need more speed, no one can prevent them from following Maxtor’s example.
ATA standard is used in millions of PCs and they are potentially ready for the new ATA HDDs to be installed. Yes, of course, older mainboards may have difficulties with HDDs of larger storage capacity. But it can be easily solved by just reflashing the mainboard BIOS. However, there is an opinion that the mainboard guys resorted to this kind of “sabotage” on purpose to force users to buy new mainboards. Because all new mainboards have no problems working with HDDs of large storage capacity.
And the users, who do not like to be blackmailed, can always get an external PCI controller card for new hard disk drives.
Maybe SATA looks very beneficial to the mainboard makers? Maybe, if we regard it as an additional feature, because the longer is the mainboard specification, the easier it is for the seller to convince the customer that he really needs this product. On the other hand, the manufacturers shouldn’t give up the regular PATA support, because there are still too many devices for this interface in the market already and even more are coming. But in this case the mainboard will have to feature additional connectors. And it pushes the prices up, especially since all today’s mainboards support SATA only due to the integrated RAID chips from third companies. Besides, these RAID chips require the connection to the PCI bus, which automatically limits their practical bandwidth from the hypothetical 150MB/sec to 133MB/sec (and why should it be better than UDMA133 then?). so, it appears that the mainboard makers do not need SATA so urgently...
Well, I get the impression that there is no one who really needs SATA interface now. But wait, we forgot to mention one more interested party: the users! Let’s figure out what the advantages are, which the users could get with a SATA hard disk drive installed in their systems. Besides, we will also share our impressions of the “first contact” with a SATA HDD:
- Thin and flexible cable.
Yes, of course the SATA cable is much more compact, and will not take up a lot of room inside the PC case. Besides, you can place it inside the case very conveniently, because it allows up to 1m length.
But since one cable allows connecting only one device to the controller card now, then a system with multiple HDDs will look very much like a snake terrarium: a mess of thin cables. Besides, who told you that the cables are flexible? All cables that I had a chance to touch were easy to bend only in one direction: along the cable. And they are absolutely non-flexible in any other direction. As a result we face a serious problem, which we will dwell on later in this article.