Hi Czerno / Bertho, > Hi Eric! On the freedos-kernel list, you voiced such opinion about > the future of big sector disks: > > " that has low priority imho, as drives with large sectors are a > temporary thing, will be gone with GPT partitions. "
This refers to the following quote from an earlier 4 kB related mail: > I stumbled upon a couple pages that say otherwise : "the industry" > has agreed to sell AF disks only *until the end of 2014*! It was actually you yourself who said that on 25 Jan 2012 ;-) AF = Advanced Format = 4096 byte per sector, i.e. "Advanced" meaning "if you find 512 byte better, you are not modern" :-p It is a bit like APS Advanced Photo System - a nice buzzword for a strange idea that is made look good for the end user. Also, "advanced" format lets more data share less ECC error correction data, squeezing out a tiny bit of extra capacity and a bit of extra resistance to data errors... Wikipedia claims that Windows Vista, 7 and 2008 have hotfixes for "drives with natively larger sectors which allow access in 512 byte emulated sectors" - in other words, the hotfix is just fixing the performance loss caused by not knowing that the underlying hardware sectors are big - while those Windows versions apparently do NOT support native big sectors yet, at least not for the boot drive... Reference for this: http://support.microsoft.com/kb/2510009 In other words, Windows Vista / 7 / 2008 makes sure to always access aligned blocks of 8 sectors of 512 bytes together, to improve performance, when it knows that the physical disk has 4 kB sector size but uses 512 byte per sector I/O protocols. That is very vaguely similar to what LBACACHE TICKLE and other read-ahead tools can do for you, if configured properly... ;-) > Manufacturers have no interest to reverting to 512 bytes sectors - > since 4K sects allows them to advertise higher capacities No. As Tom said, large sectors are only a workaround for WinXP and similar "MBR partitioned" operating systems. With GPT, you have no relevant limit to the number of sectors any more and sectors can be small again :-) On the other hand, everything is pretty virtual today anyway, and SSD / flash have better performance with access in larger blocks, but that does not mean that block has to equal sector. It could also equal cluster and FORMAT already supports making clusters of 4 kB or bigger align with 4 kB boundaries... ;-) The "virtuality" will also mean that you eventually have to load a "PC BIOS interrupts" legacy API module for EFI BIOSes. Luckily those also exist as open source, if vendors get lazy. Eric PS: As you say you read this on freedos-kernel, but are only on freedos-user (where you mailed) I took the freedom to CC both. ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Freedos-kernel mailing list Freedos-kernel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freedos-kernel
