Memory Management - Revision history

Yanli at 17:31, 20 November 2007

2007-11-20T17:31:48Z

← Older revision		Revision as of 17:31, 20 November 2007
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	Memory Management		Memory Management
	Lecture 11: Memory Management (Posted by Yan Li/100679284)		Lecture 11: Memory Management

			----------Posted by Yan Li/100679284

Yanli at 17:04, 20 November 2007

2007-11-20T17:04:13Z

← Older revision		Revision as of 17:04, 20 November 2007
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	Memory Management		Memory Management
	Lecture 11: Memory Management		Lecture 11: Memory Management (Posted by Yan Li/100679284)

YanLi: /* Hard Disk update in Linux system (extend file system space) */

2007-11-03T21:53:15Z

Hard Disk update in Linux system (extend file system space)

← Older revision		Revision as of 21:53, 3 November 2007
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	</dl>		</dl>

	Solution: cp ~~–a –one_file_sytem~~ /home /mnt/foo		Solution: cp -a --one-file-sytem /home /mnt/foo

	boot loader: It is a small piece of code located at the first block file system.		boot loader: It is a small piece of code located at the first block file system.

YanLi: /* Memory Management */

2007-11-03T04:27:30Z

Memory Management

← Older revision		Revision as of 04:27, 3 November 2007
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	Low level format is just to make disk ready to receive the data; it was used to format floppy disk. It is slow format, including set bits on the disk.		Low level format is just to make disk ready to receive the data; it was used to format floppy disk. It is slow format, including set bits on the disk.
	Modern operating systems never do low level format on hard disks, USB drives. The quick and regular format are high level format, and the difference is whether to manually erase every block. The low level format is usually to write down information on the disk to organize the internal blocks.		Modern operating systems never do low level format on hard disks, USB drives. The quick and regular format are high level format, and the difference is whether to manually erase every block. The low level format is usually to write down information on the disk to organize the internal blocks.


	==Memory Management==		==Memory Management==

YanLi: /* Lab 3 */

2007-11-03T04:26:59Z

Lab 3

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	=== Kernel debugging with GDB ===		=== Kernel debugging with GDB ===


	In brief, vmlinux is the standard kernel, and bzImage is a compressed version.		In brief, vmlinux is the standard kernel, and bzImage is a compressed version.
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	GDB is a source level debugger able to run as remote, the program being debugged is running on a different system than the one running GDB. GDB interacts with the kernel, so the target should NOT be compressed.		GDB is a source level debugger able to run as remote, the program being debugged is running on a different system than the one running GDB. GDB interacts with the kernel, so the target should NOT be compressed.


	=== File System ===		=== File System ===
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	The file system is a method of organizing files on a disk. In Linux partition table, /dev/hda represents IDE drive 1; /dev/hdb means IDE drive 2; the rest may be deduced by analogy (The PCs have limited primary partitions with four). The partition in IDE drive is distinguished by number. For instance, /dev/hda5 is the fifth partition in IDE drive 1.		The file system is a method of organizing files on a disk. In Linux partition table, /dev/hda represents IDE drive 1; /dev/hdb means IDE drive 2; the rest may be deduced by analogy (The PCs have limited primary partitions with four). The partition in IDE drive is distinguished by number. For instance, /dev/hda5 is the fifth partition in IDE drive 1.
	For SCSI drive, system uses /dev/sda, /dev/sdb and so on. USB and SATA are also considered as SCSI drive.		For SCSI drive, system uses /dev/sda, /dev/sdb and so on. USB and SATA are also considered as SCSI drive.


	=== Hard Disk update in Linux system (extend file system space)===		=== Hard Disk update in Linux system (extend file system space)===

YanLi: /* Page Fault */

2007-11-03T04:26:06Z

Page Fault

← Older revision		Revision as of 04:26, 3 November 2007
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	</dl>		</dl>

	==Page Fault==		=== Page Fault ===
	~~<dl>~~		When you load many big programs, and things just slow down. Maybe you would wonder that I do not really run these things, they should not do anything. Because they still occupy some resource, they are busy reading and writing swap file. Keep generating page fault. (If there is ever a reference to a page, first reference will trap to OS Þ page fault).
	~~<ul>~~When you load many big programs, and things just slow down. Maybe you would wonder that I do not really run these things, they should not do anything. Because they still occupy some resource, they are busy reading and writing swap file. Keep generating page fault. (If there is ever a reference to a page, first reference will trap to OS Þ page fault).

	It is important to keep the page fault rate low in page swap system. Otherwise, the effective access time increases, slowing process execution dramatically.~~</ul>~~		It is important to keep the page fault rate low in page swap system. Otherwise, the effective access time increases, slowing process execution dramatically.
	~~</dl>~~

YanLi: /* Swap */

2007-11-03T04:25:24Z

Swap

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	==Memory Management==		==Memory Management==

	==Swap==		=== Swap ===

	Swap file is a big file; swap partition is just used for swap file (pre-reserved space). In the space, the files are pre-allocated. Go throughout file interface to access them.		Swap file is a big file; swap partition is just used for swap file (pre-reserved space). In the space, the files are pre-allocated. Go throughout file interface to access them.

YanLi: /* Lab 3 */

2007-11-03T04:24:38Z

Lab 3

← Older revision		Revision as of 04:24, 3 November 2007
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	2. File System		=== File System ===

	The file system is a method of organizing files on a disk. In Linux partition table, /dev/hda represents IDE drive 1; /dev/hdb means IDE drive 2; the rest may be deduced by analogy (The PCs have limited primary partitions with four). The partition in IDE drive is distinguished by number. For instance, /dev/hda5 is the fifth partition in IDE drive 1.		The file system is a method of organizing files on a disk. In Linux partition table, /dev/hda represents IDE drive 1; /dev/hdb means IDE drive 2; the rest may be deduced by analogy (The PCs have limited primary partitions with four). The partition in IDE drive is distinguished by number. For instance, /dev/hda5 is the fifth partition in IDE drive 1.
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	3. Hard Disk update in Linux system (extend file system space)		=== Hard Disk update in Linux system (extend file system space)===

	Scenario:		Scenario:
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	<dl>		<dl>
	~~'''~~
	4. Format: high level vs. low level~~'''~~		=== Format: high level vs. low level ===

	File system is a big data structure. High level format is the process of laying down information needed so that operating system could find around on the disk.		File system is a big data structure. High level format is the process of laying down information needed so that operating system could find around on the disk.

YanLi: /* Lab 3 */

2007-11-03T04:23:20Z

Lab 3

← Older revision		Revision as of 04:23, 3 November 2007
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	=== 1. Kernel debugging with GDB ===		=== Kernel debugging with GDB ===

YanLi: /* 1. Kernel debugging with GDB */

2007-11-03T04:22:53Z

1. Kernel debugging with GDB

← Older revision		Revision as of 04:22, 3 November 2007
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	= 1. Kernel debugging with GDB =		=== 1. Kernel debugging with GDB ===