topic Re: device file in Operating System - HP-UX

device file

Indrajit Bhagat — Thu, 30 Aug 2007 06:20:50 GMT

what is the difference between the raw device file and block device file.

Re: device file

Luk Vandenbussche — Thu, 30 Aug 2007 06:25:14 GMT

http://en.wikipedia.org/wiki/Raw_device

http://en.wikipedia.org/wiki/Device_node#Block_devices

Re: device file

Pete Randall — Thu, 30 Aug 2007 06:28:29 GMT

In the simplest possible terms, the block device file provides buffered I/O while the raw device writes directly to the device in question. Typically, DB applications use the raw device and provide their own buffering mechanisms.

Pete

Re: device file

A. Clay Stephenson — Thu, 30 Aug 2007 09:23:52 GMT

The raw (character) device node is completely unbuffered whereas the "cooked" (block) device nodes interposes the buffer cache between the i/o requests and the disks.

Re: device file

whiteknight — Thu, 30 Aug 2007 11:40:05 GMT

http://docs.hp.com/en/B2355-90691/mknod.1M.html?jumpid=reg_R1002_USEN

Character and Block Special Files
Character device special files are used for devices that can transfer single bytes at a time, such as nine-track magnetic tape drives, printers, plotters, disk drives operating in "raw" mode, and terminals. To create a character special file, use the c argument.

Block device special files are used for devices that usually transfer a block of data at a time, such as disk drives. To create a block device special file, use the b argument.

The remaining arguments specify the device that will be accessible through the new special file:

major The major number specifies the major device type (for example, the device driver number).

minor The minor number specifies the device location, which is typically, but not always, the unit, drive, and/or line number.

WK
please assign points

Re: device file

Rahul Pednekar — Thu, 30 Aug 2007 16:43:45 GMT

This may help!

http://aplawrence.com/Unixart/devices.html

Thanks

RCP