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Seagate Barracuda 7200.9 HDD - 9th generation emerges

By: Cameron Johnson | HDDs in Storage | Posted: Dec 5, 2005 5:00 am
TweakTown Rating: 9.5%Manufacturer: Seagate

Drive Models


First off before we dive into this review, we want to take a look at the Seagate strategy behind the new 7200.9 series.


Seagate with the new line of drives intends to replace its current desktop line with one model from the ground up. With the 7200.8, there were only certain models available; sizes below 120GB would have required you to go back to the 7200.7 generations, not this time around though.


Seagate Barracuda ST3500641AS 500 GB Hard Drive

The 7200.9 series has models with the following specifications, 40, 80, 120, 160, 200, 250, 300, 400 and 500GB models respectively. This is truly the first drive to support all the HDD requirements from base system all the way to high end storage capacity of the lechers like me out there. What makes this line up unique are the different specifications that accompany each drive.


For example, there are drives with 2MB cache, 8MB cache and 16MB caches depending on what version and sizes are chosen.


The 40GB drives are the base model but mostly we won't see these on the retail market, OEM and system integrators will use these. This drive runs at 7200RPM with a single 40GB platter and a single read/write head. This dive uses the lowest amount of cache being 2MB and is available in PATA or SATA configuration.


The 80, 120 and 160GB models use the same setup only you can get them in either a 2MB cache or 8MB cache model with SATA or PATA connectors.


The 200 and 250GB models are set with an 8MB cache only with the 300, 400 and 500MB models using the full 16MB cache for the ultimate performance.


Compatibility and Specifications


The Seagate 7200.9 is the first to market desktop hard disk drives that are SATA 2.5 spec compliant. This has become quite confusing, in fact we even was wondering what was the deal between SATA-II and the new SATA 2.5 specifications.


In an attempt to try and remove some of the confusion, we are going to try and best explain the SATA-II and SATA 2.5 specs.


Myths and Facts


First and foremost, SATA-II is not actually a standard, but was the name of the first group of companies that came up with the additional requirements in order to become compliant with the latest high speed hard drive technologies. Though this hasn't actually stopped quite a few hard disks to come out claiming SATA-II support, although technically in order to get SATA-II compliant you only need to support two of the additional SATA extensions created by the now SATA International Organisation or known as SATA-IO. The new extensions are 3gbps transfer rate, Staggered Spin up, Speed Spectrum Clocking, Hot Plug, e.SATA, Hot Swap Native Command Queuing and click connect.


SATA 2.5 is actually a specification created by the SATA-IO. In order to obtain SATA 2.5 quality you must support ALL of the SATA-II extensions in the one drive, which we are pleased to say that the new Seagate Barracuda 7200.9 series does as well as automatic step down.


Another myth is that SATA 3G will dramatically increase the HDD speed, this is somewhat wrong. The SATA 3G connections is only between the motherboards controller and the Hard Disk cache. This means that if you pull something out of the HDD cache, you will get the full 300MB/s transfer rate, however, to retrieve something from the magnetic disks, you are back to the conventional speeds of HDD read and write delays and access times, which end up slowing the drive to around 754K/s across the platters.




Another of the new features that hasn't been elaborated on is e.SATA. Companies like Highpoint have been producing their own proprietary version of e.SATA; however, unless you use a Highpoint enclosure and highpoint controller, you won't be getting anywhere. e.SATA dramatically changes this with a new external universal port that will be used on external SATA enclosures that will support all of the SATA 2.5 specifications along with the ability to increase the cable lengths to over two meters in length due to higher shielded cables and better case grounding.


Another feature of the SATA 2.5 standards is the new Port Selector and Port Multipliers. Theses aren't part of the requirements to gain SATA 2.5 compliancy for drives, as they are designed to aid in the addition of additional SATA ports on motherboards.


Port Multiplier


The Port Multiplier works for SATA as the Hub works for USB, with some minor differences. Unlike USB, SATA is a Point to Point Direct connection between the hard disk controller and the onboard motherboard controller.


This means that you can't use a port multiplier to give yourself the same access features of USB. What we mean here is that a port multiplier will allow you to turn one Serial ATA data port into 4, 6, 8 or as many as the port multiplier PHY will allow. This does allow you to connect up all your drives, and in turn, Windows or your chosen OS will detect all the drives, however, you can't read and write simultaneously to the drives. If for example you want to retrieve data on drive 1 while writing to drive 2 at the same time, these transfers are done in order of operation. Since the port multiplier has to swap each drive over to allow the system to read and write to them, you won't get access to each drive simultaneously like you can with USB devices on the one hub.


This doesn't mean though you can't copy from one drive to another on the multiplier or use the HDD's on the multiplier to create a RAID array. It just means that you won't get the speed benefits that having the drives on separate ports like current SATA setups; it's just a way of increasing storage without increasing the amount of circuitry needed.


Port Selector


Port Selector is going to be one of the big hits for small PC offices or users who want to share a single HDD with two PCs. The Port Selector works similar to how old data switches used to work. What you have is an external HDD in an enclosure with two e.SATA ports on the back.


You then plug the SATA cables up to two separate PC's and both PC's can see the drive in Windows, but like the port multiplier, only one PC can physically send and receive data to the drive at a time, just like how LPT printer switches work with two PC's and a single printer.


Staggered Spin Up


This was quite confusing when we first heard about it. At the Seagate media briefing we learnt something that we never thought was possible.


Staggered spin up is a feature that allows drives to come on in a sequence in order to avoid massive drains on the PSU. Imagine having five or more SATA drives in a single PC. When you start this PC, you would have a massive drain on the PSU's 12v and 5v rails. This would cause even the most powerful PSU to struggle at start up.


Staggered spin up allows the drives to start up in channel order allowing drive on channel 1 to start, then channel 2 and so on until all drives are started. Staggered spin up is supported on SATA 2.5 boards. After all the drives spin up, the BIOS gets the queue to detect the HDD's on the SATA channels and booting continues unhindered. This feature has been reserved to SCSI drives and not seen in the retail drive market until the now with SATA 2.5.


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