delphij's Chaos

选择chaos这个词是因为~~实在很难找到一个更合适的词来形容这儿了……

18 Jan 2004

tjr的tfs?

junsu昨天给了我一个perforce的URL: http://perforce.freebsd.org/chv.cgi?CH=45432

tjr写道: “Initial work on a new filesystem. Right now we can mount it, list
directories, and copy small files off it, but there is no write
support yet. This is going to be a simple extent-based filesystem,
borrowing ideas from NTFS and EFS.”

那么什么是extent呢?

Google告诉我,哦,不对,是这儿,SCO……

An extent is defined as one or more adjacent blocks of data within the filesystem. When storage is added to a file on a vxfs filesystem, it is grouped in extents, as opposed to being allocated a block at a time (as is done by the s5, sfs, and ufs filesystems).

Using extents means that disk I/O to and from a file can be done in units of multiple blocks. This type of I/O can occur if storage is allocated in units of consecutive blocks. For sequential I/O, multiple block operations are considerably faster than block-at-a-time operations. Almost all disk drives accept I/O operations of multiple blocks.

感觉这个东西更适合巨个的文件?不过tfs的代码看的有些郁闷……还有,与其建立一个新的文件系统,为什么不着手在现有系统上作修改呢?就像EFS之于NTFS?


Archived: 1 Comment

delphij | January 18, 2004 3:43 AM

值得一看的东东:SCO关于vxfs的介绍

DragonFly那边好像也有人做这个,不过是把vxfs整过去,听说BSDL’ify了?