[Klug-general] Hard Drives

Sun Apr 17 11:31:28 UTC 2011

Hi Peter

PATA was the amalgamation of EIDE and ATA into one loose term.  Since PATA was introduced two separate ATA standards came along, ATA-4 and ATA-6 so you can find disks and interfaces that support either.

I meant to say "Now lets now do SATA vs USB" not "Now lets no SATA vs USB".

You can buy a SATA PCI card for under a tenner these days mail order.

On 17 Apr 2011, at 11:47, Peter Childs wrote:

> On 17 April 2011 11:26, James Blake <jimmyblake at gmail.com> wrote:
>> Hi Peter
>> I guess the answer, as always, is that it depends what you're trying to do.
>> First SATA vs PATA:
>> 
>> PATA: with ATA-4 33 Mbps / with ATA-6 100 Mbps
>> SATA: 1.5 Gbps
>> SATA II: 3 Gbps
>> 
>> So SATA is a no brainer.  Now lets no SATA vs USB:
> 
> Don't you mean PATA.
> 
> Except the machine upstairs with only a 40Gb PATA drive does not have
> SATA sockets..... But otherwise PATA is legacy hardware as is most
> defiantly a no brainier unless you have no other option......
> 
>> 
>> USB 1.1: 12 Mbps
>> USB 2.0: 480 Mbps
>> 
>> You'll still be constrained by the drive electronics in the enclosure as
>> well, so internal SATA is a no brainer for transfer speed.  If you need to
>> swap the drive between two machines get SATA toaster docks on both machines
>> that connect to your machine's internal or external SATA interface and you
>> simply plop the drive in - full SATA speed with USB-drive portability.
>> NAS over Gigabit Ethernet:
> 
> So the only advanage really of USB is that its portable, So long as
> your using USB 2 (or even 3) which is somtimes difficult to check, you
> should not notice the speed degrade, its still 4x faster than PATA!
> (so long as its not using a PATA disk inside, which I suspect may
> happern on older machines).

You've got it, but there aren't that many PATA enclosures floating around these days (the cabling was clunky).  These speeds are all theoretical, USB 2 rarely reaches over 280 Mbps.  Similarly, USB 3 offers 5 Gbps, but the drives have in no way reached anywhere near these speeds.  In addition, but you'll still be limited by the internal drive speeds of SATA. 

> 
>> 
>> 1 Gbps (theoretical)
>> 
>> Again, you'll still be constrained by the drive electronics in the enclosure
>> as well.  I've got a couple of Drobo's here - great for redundancy and
>> multi-protocol sharing (through the DroboShare, but nothing you can't do
>> with internal SATA drives and in a Linux box.
>> James
> 
> I did a bit of reading up on NAS and it goes a bit like this......
> 
> SATA or SCSI Hard Disk..... -> OS (Probably a streamlined version of
> BSD, Linux or somthing else) -> Samba, NFSd, FTPd etc -> Network -> OS
> of Client...
> 
> Hence it will cost you around £100 for an extra specilist device and
> adds and extra layer of processing, hence 1Gb just ain't going to
> happen, infact I suspect you'll be lucky to see 100Mbit/s even on
> 1Gbit/s Ethernet......
> 
> The other thing to watch is 1GBs = 8Gbs  and the terms get mixed up
> all the time and give most people a head ache.
> 
> I'm still trying to work out how big to go as big is usually cheaper
> in terms of £ per a Gig (untill it gets very very very big) but when
> does speed and reliability stop it from being worth going any bigger.

1 Gbps is never going to happen anyway due to the protocol encode/decode overheads, unless you want to drop some TOE (TCP Offload Engine) cards into the NAS and all clients as well.

In my humble opinion, and I have used Linux (DroboShare), Windows (Windows Home Server) and MacOS (Time Capsule) NAS devices, I got better granularity of configuration, better performance and increased capacity running my shares off of a server - but there is a higher electricity cost. 

> Peter.
> 
>> 
>> On 17 Apr 2011, at 10:39, Peter Childs wrote:
>> 
>> My Linux Hard Disk has just failed..... Groan, not very much data
>> except OS on it so that will be easy to sort out...... (Looks like its
>> the Disk Controller thats failed not the disk as it works when it
>> feels like it) Its a SATA.....
>> 
>> Now need to get a new one, Whats the best way to go.
>> 
>> Speed Vs Size Vs Cost Vs Reliability....
>> 
>> meaning
>> 
>> SATA Vs PATA Vs USB Vs NAS
>> 
>> Also need to upgrade that machine upstairs running Myth on a 40Gig
>> Disk which only takes PATA (Not SATA)
>> 
>> Any suggestions which way to go?
>> 
>> Peter.
>> 
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