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[转帖]MS－DOS各类版本的特点及区别
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MS－DOS各类版本的特点及区别
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Digital Research公司曾以它开发的CP/M-80操作系统独占8位微机市场。但IBM公司选定的早期版本DOS1.00及DOS1.10,是由MicroSoft公司将所购买的8位机CP/M操作系统作了改进,而使该公司目前掌握着16位微机操作系统的大部分市场。当今,MS-DOS操作系统,已经成为自然形成的惯用标准,也是低档16位微机用户的通用操作系统。为此,本文介绍各类DOS版本的特点及主要区别,以利于读者根据自己的机型档次来选择合适的DOS版本,以避免在低档机上盲目追求高版本。
DOS 1.00及DOS1.10是8086/8088的CP/M操作系统的扩充版,是8位微机用到16位微机的CP/M操作系统的改进。它的功能简单,不支持硬盘,提供的应用程序也不多。
DOS2.00版比DOS1.10版在结构上有很大扩充。主要增加的部分是提供了UNIX的部分使用界面。在其结构上的重大改进是:支持一个或多个固定盘。固定盘能划分分区,每个分区可用不同的操作系统。从DOS2.00开始,DOS按每个磁道九个扇区格式化软件。 磁盘缓冲区是DOS启动时保留的一片用户内存区，执行盘操作时，DOS2.00允许你指定启动系统时保留的缓冲区数目从1-99之间选择。如果在内存很大的情况下，设置多个缓冲区，会使你的程序运行得更快。支持树形结构目录，这一新的特征允许你把同一磁盘上的所有相关的各组文件放在它们自己的目录下面，各个目录彼此隔离。从根目录开始按逻辑顺序看目录时，目录结构就象树形结构一样一目了然。增加了磁盘卷标记。扩展的屏幕和键盘控制功能，能在程序中送出特殊的字符串控制屏幕颜色和光标位置。还允许你重新定义键盘上任何键的意义。增加了标准输入输出的管道功能，用特殊的字符“”(输出)能使程序接收来自非键盘的外部输入或指定输出到非屏幕的目的设备上，增加了标准输入输出的流水作业，使DOS像“流水线”一样，从第一个程序的输出指向第二个程序的输入。特殊字符“、\”对于DOS有了新的意义，已不能再在文件名中使用了。增加了一些命令，如ASSING，BACKUP，BREAK，CLS ，CTTY，ECHO，IF 。FOR ，SHIFT，GOTO，FDISK，GRAPHICS，MKDIR，RMDIR，CHDIR，PATH，PRINT，PROMPT，REC。VER，RESTORE，SET ，TREE，VER ，VERIFY，VOL等。
在DOS2.00版上，对系统内部作了修改，是为了能适用于PC/TR及PC PORtable(轻便型)的半高型软盘驱动器特性，而没有增加任何新的命令，仍占有内存24KB。
1984年推出DOS3.00版，是为PC/AT机而发表的。可以支持IBM PC/AT机所配置的1.2MB高密软盘驱动器和20MB的大容量硬盘。还提供了一个虚拟磁盘(Virtual disk)，就是利用内存贮器模拟的磁盘。系统占用36KB。外部命令可以加上一个前列字符串，用以描述命令所在的子目录，在内部命令文件分配表(FAT)上作了重大改变。文件分配表每一项以16位二进制数表示而不是以12位二进制数表示。因此一个磁盘中最多有65536簇，而不是原来的4096簇，而簇的大小意味着同一大小的磁盘中，每一个簇可以有较小的空间，这样磁盘的空间使用会更有效。还增加了多用记系统和网络用户所需的文件共享功能。增加了系统功能调用而加强了文件管理能力。支持Basic3.0版，允许用户自行安装基于Basic的设备驱动程序和执行DOS命令?.
DOS3.10版占用内存空间36KB不变。主要增加了网络功能,提供了SUBST,JOIN命令,如果不使用网络功能,DOS3.10版本DOS3.00版几乎完全相同。
DOS3.2版是为经便型PC机而发表的,主要增加了3.5英寸720KB软盘驱动器功能,另外还增加了REPLACE、XCOPY等命令及令牌网络功能和I/O控制。
DOS3.30版的特点是增加了一些新设备驱动程序和一些外部命令,如DISPLAY.SYS、APPEND等,增加了码页的概念,除可用于PC/XT、AT长城系列机外,还可用在IBM PS/2机上。
DOS4.0版于1988年6月推出,随后推出的4.01版本可支持全部的IBM PS/2家族。
DOS4.××版的特点有:支持大的硬盘分区,在DOS3.3之前,磁盘基本DOS分区最大容量限制在33MB之内,而DOS4.××版本,基本DOS分区可大于33MB,其缓冲区由99 增到10000个,这种变化可以大大改进DOS磁盘性能,加快程序运行。扩充的FASTOPEN功能,可以极大地改进大的磁盘文件随机存取性能。
从以上可知,除DOS3.10是为增加网络功能的需要外,其它版本的变更主要是为磁盘机的升级而推出的.
Characteristics and Differences of Various Versions of MS-DOS
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The Digital Research company once monopolized the 8-bit microcomputer market with its developed CP/M-80 operating system. But the early versions DOS 1.00 and DOS 1.10 selected by IBM were improved by Microsoft Corporation from the purchased 8-bit CP/M operating system, and thus the company currently holds most of the market for 16-bit microcomputer operating systems. Nowadays, the MS-DOS operating system has become a naturally formed customary standard and is also a general operating system for low-end 16-bit microcomputer users. Therefore, this article introduces the characteristics and main differences of various DOS versions, so as to help readers select a suitable DOS version according to the grade of their machine models and avoid blindly pursuing high versions on low-end machines.
DOS 1.00 and DOS 1.10 are extended versions of the 8086/8088 CP/M operating system, which is an improvement of the 8-bit microcomputer to 16-bit microcomputer CP/M operating system. Its functions are simple, it does not support hard disks, and there are not many application programs provided.
DOS 2.00 version has a great expansion in structure compared with DOS 1.10 version. The main added part is providing part of the use interface of UNIX. The major improvement in its structure is: supporting one or more fixed disks. Fixed disks can be partitioned, and each partition can use different operating systems. Starting from DOS 2.00, DOS formats software with nine sectors per track. The disk buffer is a piece of user memory area reserved when DOS is started. When performing disk operations, DOS 2.00 allows you to choose the number of buffers reserved when starting the system from 1 to 99. If there is a large amount of memory, setting multiple buffers will make your program run faster. It supports a tree-structured directory. This new feature allows you to place all related groups of files on the same disk under their own directories, and the directories are isolated from each other. When viewing directories from the root directory in logical order, the directory structure is as clear as a tree structure. Disk volume labels are added. Extended screen and keyboard control functions can send special string controls to the screen color and cursor position in the program. It also allows you to redefine the meaning of any key on the keyboard. The pipeline function of standard input and output is added. The special character "" (output) can make the program receive external input from non-keyboard or specify output to non-screen destination devices. The water flow operation of standard input and output is added, making DOS like a "pipeline" where the output of the first program points to the input of the second program. The special characters "" and "\" have new meanings for DOS and can no longer be used in file names. Some commands are added, such as ASSING, BACKUP, BREAK, CLS, CTTY, ECHO, IF, FOR, SHIFT, GOTO, FDISK, GRAPHICS, MKDIR, RMDIR, CHDIR, PATH, PRINT, PROMPT, REC, VER, RESTORE, SET, TREE, VER, VERIFY, VOL, etc.
On the DOS 2.00 version, modifications were made to the system interior to be suitable for the characteristics of the half-high floppy disk drives of PC/TR and PC PORtable (portable) machines, and no new commands were added, still occupying 24KB of memory.
The DOS 3.00 version was launched in 1984 for the PC/AT machine. It can support the 1.2MB high-density floppy disk drive and 20MB large-capacity hard disk configured by the IBM PC/AT machine. It also provides a virtual disk (Virtual disk), which is a disk simulated by using memory. The system occupies 36KB. The external command can be prefixed with a string to describe the subdirectory where the command is located, and a major change is made in the internal command file allocation table (FAT). Each item of the file allocation table is represented by a 16-bit binary number instead of a 12-bit binary number. Therefore, a disk can have a maximum of 65536 clusters instead of the original 4096 clusters, and the size of the cluster means that in a disk of the same size, each cluster can have a smaller space, so the disk space usage will be more efficient. File sharing functions required by multi-user systems and network users are also added. System function calls are increased to strengthen file management capabilities. It supports Basic 3.0 version, allowing users to install device drivers based on Basic and execute DOS commands by themselves.
The DOS 3.10 version still occupies 36KB of memory space. It mainly adds network functions and provides SUBST and JOIN commands. If the network function is not used, the DOS 3.10 version is almost exactly the same as the DOS 3.00 version.
The DOS 3.2 version is launched for the portable PC machine. It mainly adds the function of the 3.5-inch 720KB floppy disk drive, and also adds commands such as REPLACE, XCOPY, and token network functions and I/O control.
The characteristics of the DOS 3.30 version are adding some new device drivers and some external commands, such as DISPLAY.SYS, APPEND, etc., adding the concept of code pages. It can be used not only for PC/XT, AT Great Wall series machines but also for IBM PS/2 machines.
The DOS 4.0 version was launched in June 1988, and the subsequent 4.01 version can support all the IBM PS/2 family.
The characteristics of the DOS 4.×× version are: supporting large hard disk partitions. Before DOS 3.3, the maximum capacity of the basic DOS partition was limited to within 33MB, while for the DOS 4.×× version, the basic DOS partition can be larger than 33MB, and the buffer is increased from 99 to 10000, which can greatly improve the DOS disk performance and speed up program operation. The expanded FASTOPEN function can greatly improve the random access performance of large disk files.
From the above, it can be seen that except that DOS 3.10 is for the need of adding network functions, the changes of other versions are mainly launched for the upgrade of disk drives.
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