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HDD Manufacturers Moving To 4096-Byte Sectors
Luminous Coward writes "As previously discussed on Slashdot, according to AnandTech and The Tech Report, hard disk drive manufacturers are now ready to bump the size of the disk sector from 512 to 4096 bytes, in order to minimize storage lost to ECC and sync. This may not be a smooth transition, because some OSes do not align partitions on 4K boundaries."
According to the Anandtech article, only the pretty much end-of-life Windows XP is out of luck. Linux, OS X and modern Windows versions all work ...
Non news?
There are certain models of the Western Digital Caviar Green drives that are already shipping with a 4K sector size, such as this one: http://www.newegg.com/Product/Product.aspx?Item=N82E16822136490
A sector on a HDD is the minimum writeable space. Think of it as a lot in a subdevelopment. If each lot is 50,000 sq. ft. on a 20 acre plot, and you move to 60,000 sq. ft. lots instead, the plot is still 20 acres, but the development now has less lots on it.
In computers, larger sectors are often better for large files, while smaller sectors are better for smaller partitions and smaller files. If a sector is 4096 bytes, and you create a 1024 byte file, it still occupies 4096 bytes on the disk, as the HDD won't write anything else but that file to the sector. If you have files that are hundreds of megabytes though, you can access the file, with minimum wastage, by using fewer sectors, which reduces thrashing and similar issues.
The discrepancy between file sizes and sector sizes is what the difference is in Windows when you view a hard drive and it displays "size" and "size on disk". "Size" is the actual file size, while "size on disk" is the amount of space the file occupies on the hard drive.
FanFictionRecs.net
Those are "logical" sectors, which can be different from the physical sector size. According to the Anandtech article the Western Digital hard drive model numbers that end with "EARS" use the larger, 4KB physical sector size, while presenting a 512 byte logical sector size to the operating system for compatibility reasons.
Please note, of course, that the logical sector size is a drive interface level concept distinct from the filesystem cluster or block size. Filesystem block sizes have generally been larger than the logical or physical sector size for quite some time.
That's insane. ECC at the hardware / firmware level corrects the vast majority of bit errors transparently in a manner that is invisible to the operating system. If you took out sector level ECC, the drives would be useless in anything other than a ZFS RAID configuration, and even then performance would drop in the presence of trivially ECC correctable errors, due to the re-reads and stripe reconstructions at the filesystem level.
Drive performance would probably drop because the heads would have to stay in closer alignment without the ability of ECC to correct data read errors caused by small vibrations and electrical noise. In addition, sector relocations would probably increase because tiny flaws that do not impair the ability of a drive to write an ECC correctable sector would force the drive to remap that sector to another part of the disk.
It is a similar issue with various wire level data transmission schemes. If DSL connections did not use error correcting codes, they would suffer much higher packet loss rates than they do now, especially at distance. Most those packets would generally get retransmitted due to transport level checksum errors, but why resort to performance impairing fall back measures when the problem can be largely eliminated at a lower level?
I believe that some of the early CDC machines (a company that is no longer around) had a 6-bit character. The Digital Equipment Company (DEC, alos a company that is no longer around) PDP-1, maybe the PDP-20, and some others also had a 6-bit character. The PDP's had 36-bit words, packing 6 characters into a word. And of course, the IBM machines (a company that is still around) used EBCDIC rather than ASCII (but did use an 8-bits per character). Some of the earlier (and even the 370's) IBM machines used BCD (binary coded decimal) for arithmetic (packing a number from 0 to 9 in 4 bits, with some sign and unassigned bits left over).
Also, back in the IBM JCL days, when allocating disk space for a file you could specify the number of cylinders (or tracks) that you wanted, the block size and the packing factor.
What a bunch of misinformed drivel. That article is missing a couple of things:
firstly) The issue affects all Windows versions based on a 5.x kernel. That means Windows 2000, XP, 2003 server and Windows Home Server.
1) These drives are NOT strictly-4k-sector. The platters may be organized in 4k sectors, but the drive only talks to the OS in terms of 512 byte-sectors. And since we're discussing old Windows versions: NTFS has defaulted to using 4k (logical) sectors since its introduction, so there is NO performance penalty when using NTFS on these drives. You shouldn't be using FAT32 anyway.
2) The issue can be worked around by creating partitions with a tool that understands 4k sectors, or by re-aligning the partitions after creation/installation. If you only use a drive in those systems (i.e. no repartitioning), the drive will work as it should. Even if you create partitions that are unaligned, the drive will still work - you will only lose some performance.
3) The one genuine problem raised in the linked article comes when you want to use these drives in closed-firmware devices. In this case you still have two options: either you use the WD-provided jumper setting, or you pre-create the partitions before you insert the drive.
I fail to see what the fuss is all about.