<?xml version="1.0" encoding="utf-8" ?><rss version="2.0"><channel><title><![CDATA[password636的专栏]]></title><description><![CDATA[]]></description><link>https://blog.youkuaiyun.com/password636</link><language>zh-cn</language><generator>https://blog.youkuaiyun.com/</generator><copyright><![CDATA[Copyright &copy; password636]]></copyright><item><title><![CDATA[Static RAM ]]></title><link>https://blog.youkuaiyun.com/password636/article/details/1720397</link><guid>https://blog.youkuaiyun.com/password636/article/details/1720397</guid><author>password636</author><pubDate>Wed, 01 Aug 2007 00:02:00 +0800</pubDate><description><![CDATA[SRAM versus DRAMDRAM:Memory technologyPC memory is dominated by DRAMCharacterized by the fact that it must be constantly accessed or it will lose its stored data.NEED: create highly specialized and co]]></description><category></category></item><item><title><![CDATA[Abstraction Levels]]></title><link>https://blog.youkuaiyun.com/password636/article/details/1718003</link><guid>https://blog.youkuaiyun.com/password636/article/details/1718003</guid><author>password636</author><pubDate>Mon, 30 Jul 2007 23:50:00 +0800</pubDate><description><![CDATA[what are abstraction levels?what are drivers?what are APIs?what are four basic parts of computer hardware?what are three busses of a typical computer?what are PCI, ISA, AGP, PC-105, VXI and so forth?w]]></description><category></category></item><item><title><![CDATA[关于逻辑的一点体会]]></title><link>https://blog.youkuaiyun.com/password636/article/details/1648388</link><guid>https://blog.youkuaiyun.com/password636/article/details/1648388</guid><author>password636</author><pubDate>Tue, 12 Jun 2007 00:07:00 +0800</pubDate><description><![CDATA[书摘离散数学的基础有三个主要内容：逻辑，集合和函数（《离散数学及其应用第四版》）。逻辑为什么有这样的地位？书中先讲了三点。1. Logic has rules. 这些规则给出了数学语句的准确含义。2. 逻辑是所有数学推理的基础。3. 逻辑在许多方面的实际应用：计算机的设计，计算机程序的设计等领域。集合为什么有这样的地位？所有的离散结构都是从集合构造而来，也即没有集合就没]]></description><category></category></item><item><title><![CDATA[Redirect]]></title><link>https://blog.youkuaiyun.com/password636/article/details/751408</link><guid>https://blog.youkuaiyun.com/password636/article/details/751408</guid><author>password636</author><pubDate>Tue, 23 May 2006 16:10:00 +0800</pubDate><description><![CDATA[command filename2 　　把command命令以filename文件作为标准输入，以filename2文件作为标准输出command command command >&m 　　　把标准输出重定向到文件描述符m中command 0 standard input1 standard output2 standard errorWe assume that cout and ce]]></description><category></category></item><item><title><![CDATA[4.5. File Access Permissions]]></title><link>https://blog.youkuaiyun.com/password636/article/details/743339</link><guid>https://blog.youkuaiyun.com/password636/article/details/743339</guid><author>password636</author><pubDate>Wed, 17 May 2006 23:30:00 +0800</pubDate><description><![CDATA[4.5. File Access Permissions"All the file types (directories, character special files, and so on) have permissions. Many people think only of regular files as having access permissions." Access ]]></description><category></category></item><item><title><![CDATA[IDs associated with each process and file’s mode word]]></title><link>https://blog.youkuaiyun.com/password636/article/details/743181</link><guid>https://blog.youkuaiyun.com/password636/article/details/743181</guid><author>password636</author><pubDate>Wed, 17 May 2006 21:54:00 +0800</pubDate><description><![CDATA[IDs associated with each process and file’s mode word IDs associated with each processEvery process has seven or more IDs associated with it. The basic seven IDs are: process ID, real IDs (real ]]></description><category></category></item><item><title><![CDATA[Process ID and special processes ]]></title><link>https://blog.youkuaiyun.com/password636/article/details/742674</link><guid>https://blog.youkuaiyun.com/password636/article/details/742674</guid><author>password636</author><pubDate>Wed, 17 May 2006 14:51:00 +0800</pubDate><description><![CDATA[Process ID and special processes (From 8.2. Process Identifiers) Process ID1. Keywords: unique, reuse 2. "unique”: "Because the process ID is the only well-known identifier of a process th]]></description><category></category></item><item><title><![CDATA[File Types]]></title><link>https://blog.youkuaiyun.com/password636/article/details/740298</link><guid>https://blog.youkuaiyun.com/password636/article/details/740298</guid><author>password636</author><pubDate>Tue, 16 May 2006 00:02:00 +0800</pubDate><description><![CDATA[/usr/include/bits/stat.h/* Encoding of the file mode.*//*取位宏，000 001111 000 000 000 000*/#define __S_IFMT        0170000 /* These bits determine file type.*//*7种文件类型宏*//* File types.*/#def]]></description><category></category></item><item><title><![CDATA[ANSI history]]></title><link>https://blog.youkuaiyun.com/password636/article/details/729230</link><guid>https://blog.youkuaiyun.com/password636/article/details/729230</guid><author>password636</author><pubDate>Mon, 15 May 2006 11:31:00 +0800</pubDate><description><![CDATA[ANSI history:1918年10月19日         美国工程标准委员会(AESC)1928年AESC改组为      美国标准协会(ASA)1966年8月又改组为      美利坚合众国标准学会(USASI)1969年10月6日始改为  美国国家标准学会(ANSI)总部设在纽约American Engineering Standards Committee->American Sta]]></description><category></category></item><item><title><![CDATA[2.1. Introduction]]></title><link>https://blog.youkuaiyun.com/password636/article/details/729186</link><guid>https://blog.youkuaiyun.com/password636/article/details/729186</guid><author>password636</author><pubDate>Mon, 15 May 2006 11:07:00 +0800</pubDate><description><![CDATA[Reason for UNIX standardization: 1.The proliferation of versions and differences during the 1980s. (Crazy 1980s.)2.Many large users.(Large ones always work.)In this chapter:1. Look at the various st]]></description><category></category></item><item><title><![CDATA[练习(Exercises)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/726828</link><guid>https://blog.youkuaiyun.com/password636/article/details/726828</guid><author>password636</author><pubDate>Sat, 13 May 2006 00:33:00 +0800</pubDate><description><![CDATA[练习(Exercises)1.1在你的系统上查证除根目录外，目录. 和.. 是不同的。1.2在程序figure1.6的输出中，进程ID为852和853的进程发生了什么?1.3在section 1.7中，perror的参数是用ISO C的属性const定义的，而rerror的整型参数(integer argument)则没有用此属性定义，为什么?1.4在附录B中的出错处理函数err_sy]]></description><category></category></item><item><title><![CDATA[1.12. 总结(summary)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/726824</link><guid>https://blog.youkuaiyun.com/password636/article/details/726824</guid><author>password636</author><pubDate>Sat, 13 May 2006 00:26:00 +0800</pubDate><description><![CDATA[1.12. 总结(summary)本章快速浏览了UNIX。我们描述了一些以后会多次见到的基本术语。我们已经见到了许多小的UNIX程序例子，从中可感知到本书的其余部分将会进一步介绍的内容。下一章是关于UNIX的标准化，以及该领域的工作对当代系统的影响。标准，特别是ISO C和POSIX.1标准将影响本书的余下部分。]]></description><category></category></item><item><title><![CDATA[1.11.系统调用和库函数(System Calls and Library Functions)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/726820</link><guid>https://blog.youkuaiyun.com/password636/article/details/726820</guid><author>password636</author><pubDate>Sat, 13 May 2006 00:20:00 +0800</pubDate><description><![CDATA[1.11.系统调用和库函数(System Calls and Library Functions)所有的操作系统都提供服务点(service points)，程序通过服务点向内核请求服务。UNIX系统的所有实现都提供经良好定义的有限数目的入口点(a well-defined, limited number of entry points)，这些入口点是directly into the ker]]></description><category></category></item><item><title><![CDATA[1.10. 时间值(Time Values)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/725331</link><guid>https://blog.youkuaiyun.com/password636/article/details/725331</guid><author>password636</author><pubDate>Thu, 11 May 2006 23:34:00 +0800</pubDate><description><![CDATA[1.10. 时间值(Time Values)长期以来，UNIX系统一直使用两种不同的时间值：(1)日历时间(calendar time)。该值是自1970年1月1日00:00:00以来国际标准时间(Coordinated Universal Time (UTC))所经过的秒数累计值（早期的手册称UTC为格林尼治标准时间）。这些时间值可用于记录文件最近一次的修改时间等。(2)进程时间(Process]]></description><category></category></item><item><title><![CDATA[1.9.信号(Signals)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/725278</link><guid>https://blog.youkuaiyun.com/password636/article/details/725278</guid><author>password636</author><pubDate>Thu, 11 May 2006 23:00:00 +0800</pubDate><description><![CDATA[1.9.信号(Signals)信号是通知一个进程已发生某种条件的一种技术(a technique used to notify a process that some condition has occurred)。例如，若某一进程执行除法操作，其除数为0，则名为SIGFPE(浮点数异常floating-point exception)的信号将被发送给该进程。进程如何处理信号有三种选择：(1) 忽]]></description><category></category></item><item><title><![CDATA[1.7.出错处理(Error Handling)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/724079</link><guid>https://blog.youkuaiyun.com/password636/article/details/724079</guid><author>password636</author><pubDate>Thu, 11 May 2006 12:55:00 +0800</pubDate><description><![CDATA[1.7.出错处理(Error Handling)当UNIX函数出错时，通常返回一个负值，并且整数errno通常设置为具有附加信息意义的一个值。(unbuffered I/O functions:open,read,write,lseek和close发生错误的时候都是返回-1并设置errno)例如，open函数如成功执行则返回一个非负文件描述符，如出错则返回－1。在open出错时，有大约1 5种不同]]></description><category></category></item><item><title><![CDATA[1.6.程序和进程(Programs and Processes)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/722815</link><guid>https://blog.youkuaiyun.com/password636/article/details/722815</guid><author>password636</author><pubDate>Wed, 10 May 2006 22:56:00 +0800</pubDate><description><![CDATA[1.6.程序和进程(Programs and Processes)程序(Program)一个程序是一个存储在磁盘上某个文件夹中的可执行文件。A program is read into memory and is executed by the kernel as a result of one of the six exec functions. Section 8.10将说明这些exec函]]></description><category></category></item><item><title><![CDATA[1.5.输入和输出(Input and Output)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/722367</link><guid>https://blog.youkuaiyun.com/password636/article/details/722367</guid><author>password636</author><pubDate>Wed, 10 May 2006 17:54:00 +0800</pubDate><description><![CDATA[1.5.输入和输出(Input and Output)文件描述符(File Descriptors)正常地，文件描述符是非负的小整数(small non-negative integers:0,1,2...)。文件描述符出现的原因是为了kernel能够识别一个进程正在存取的所有文件。无论何时kernel打开一个存在的文件或者创建一个新的文件，它都返回一个文件描述符，以便我们随后能够使用文件描述]]></description><category></category></item><item><title><![CDATA[7.9.环境变量(Environment Variables)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/715771</link><guid>https://blog.youkuaiyun.com/password636/article/details/715771</guid><author>password636</author><pubDate>Tue, 09 May 2006 23:43:00 +0800</pubDate><description><![CDATA[7.9.环境变量(Environment Variables)正如我们前面提到的那样，环境字符串(environment strings)通常是这样的格式：name=valueUNIX kernel从来都不理会(look at)这些字符串；它们的解释(interpretation)是由各种各样的应用程序来做的。比如shell就使用了许多环境变量。一些环境变量是在登录的时候就自动地被设置了，比如]]></description><category></category></item><item><title><![CDATA[7.5.环境列表(Environment List)]]></title><link>https://blog.youkuaiyun.com/password636/article/details/715241</link><guid>https://blog.youkuaiyun.com/password636/article/details/715241</guid><author>password636</author><pubDate>Tue, 09 May 2006 17:40:00 +0800</pubDate><description><![CDATA[7.5.环境列表(Environment List)每一个程序也被传入一个环境列表。象参数列表(argument list)一样，环境列表也是一个字符指针的数组，其中每个指针指向一个以null结束的C字符串(null-terminated C string)。这个指针数组的地址被包含在全局变量environ中:extern char **environ;例如，如果环境由五个字符串组成，环境列表]]></description><category></category></item></channel></rss>