Seagate Firmware Performance Differences 177
Derkjan de Haan writes "The Seagate 7200.10 disk was the first generally available desktop drive featuring perpendicular recording for increased data density. This made higher-capacity disks with excellent performance cheaper to produce. Their sequential throughput actually exceeded that of the performance king — the Western Digital Raptor, which runs at 10,000 RPM vs. the more common 7,200 RPM. But reports began to surface on the Net claiming that some 7200.10 disks had much lower performance than other, seemingly identical disks. Attention soon focused on the firmware, designated AAK, in the lower-performing disks. Units with other firmware, AAE or AAC, performed as expected. Careful benchmarks showed very mixed results. The claims found on the Net, however, have been confirmed: the AAK disk does have a much lower throughput rate than the AAE disk. While firmware can tune various aspects of performance it is highly unusual for it to affect sequential throughput. This number is pretty much a 'fact' of the disk, and should not be affected by different firmware."
Re:Linux check (Score:3, Informative)
Wouldn't you know that I've got an AAK disk.
Why the mixed results? (Score:2, Informative)
Sadly, we can't tell, because the author has focussed on the sensationalism of poor performance rather than asking these questions. Seems to need a few more experiments setting up, or alternatively an answer from the horse's mouth.
Some candidate theories:
- microcontroller software bug (unlikely)
- hardware cost-down such as a slower, cheaper microcontroller or less RAM on the drive (quite likely)
- rebalancing the performance optimisation, changing the cacheing or readahead algorithms to suit typical loads (possible, but it seems odd that this would limit linear read performance)
It's true (Score:5, Informative)
I have been setting up a couple of 8-drive RAID-5 arrays with these drives for some customers, and I also found out that 3.AAE drives performed much better that 3.AAK. No idea why. Seagate was unresponsive to queries about flashing the firmware and I had to replace all the 3.AAK drives by 3.AAEs.
The manufacturing country had nothing to do with it. I had some chinese 3.AAE and 3.AAK as well as taiwanese (or was that thai?) 3.AAE and 3.AAK. 3.AAE would always perform better.
The kind of testing I performed was:
Also, if you buy a retail kit (which I found cheaper than OEM at Fry's), there is no way to find out the firmware level on the box. You had to open the retail boxes to check the firmware revision on the drive itself.
One theory I have is that these drives can supposedly be configured for server or workstation workloads. It could be that AAK drives are configured for server workloads by default (unless overridden) while the AAE are configured for workstation workloads by default. I have no idea how to toggle this under Linux.
Re:Not really same drives (Score:4, Informative)
They were selling a USB 802.11G dongle (Model DWG-122, IIRC), one model number, *THREE* different chipsets (each requiring different drivers, only one of which had drivers for other than Windows)
Nothing on the box other than a "A" "B" or "C" in tiny print in a corner.
Observation from the "inside" (Score:5, Informative)
A hard drive is a very complex subsystem inside your computer, more complex than many people realize. A hard drive contains one or more CPUs, memory, firmware, and dedicated hardware devoted to the functions of storing and retrieving data.
There is no single "right" way to draw the line between what is firmware and what is hardware in a hard drive. Algorithms could be coded in VHDL or Verilog and synthesized into the silicon, or they could be compiled in C (or hand coded in assembly) and be embedded in firmware. Each drive company has their own philosophy for where to draw the line.
Some drive companies choose to implement only fundamental functions in silicon, and implement everything else in firmware. For these companies, comparing their firmware to the BIOS in a PC is a poor analogy. A better analogy would be to compare the firmware to the operating system.
In a system with "lite" firmware, the firmware typically would be responsible for configuring a few control registers and buffers, and then the hardware would take over. But for a system with "heavy" firmware, the firmware behaves much more like a kernel. Data is not going to be moved in or out of buffers, or be sent to and from platters, without the active involvement of the firmware scheduling and ordering that activity.
The author of the OP wrote "it is highly unusual for (firmware) to affect sequential throughput". The author is wrong. In a system with "heavy" firmware, all performance is highly dependent on the firmware. It can easily make the same difference in performance as you would see running Windows 95 v. Windows XP v. Windows Vista v. RH 7.2 v. RHEL 3.0 on the same PC hardware.
I do not know if the Seagate drive in question is a "heavy" or "lite" firmware drive, but I do know that the assumption that firmware takes a minor role in hard drive performance is mistaken.
Not a bug, it is an OEM feature (Score:2, Informative)