"November 6, 1978 Microsoft announces the availability of Microsoft EDIT-80, a random access, line oriented text editor for 8080 and Z-80 systems. EDIT-80 is the first microcomputer editor with random line access to floppy disk files."
https://channel9.msdn.com/Series/History/The-History-of-Microsoft-1978
The Z80 uses 8-bit bytes which are stored in memory. These bytes contain both the program that the processor is executing and the data items that the program is working on. The processor uses 16-bit addresses to access these bytes, so there can be anything up to 64k (65536) bytes of memory.
GW-BASIC/MATH1.ASM
3829 lines (3652 sloc) 115 KB
; [ This translation created 10-Feb-83 by Version 4.3 ]
在一台64GB内存的电脑编辑一个115GB的文件，做个像Unix的ed那样的"line-oriented text editor"，基本思路是什么？开源EDIT-80可能更有用。
fseek是有的：Some basic INT 21h function calls present since DOS version 2.0
AH = 42 Set file position
AL=origin of move, 0-start, 1-current, 2-end
BX=file handle
CX:DX=(signed) offset
https://enacademic.com/dic.nsf/enwiki/9629368
要在最开始插入一行怎么办？ed的o(pen)命令?怎么实现？我怀疑/很不肯定地记得：也是处理大文件时会切分成小文件（临时工作文件），如每64KB一个文件，这样不用把整个文件"memmove"下。
再说，微软并没有提供build tools等，说不定上传前整理了下代码，把math1a.asm, math1b.as, ... math1z.asm或者sin.asm, cos.asm等合并成了math1.asm
Other 1976:
Shugart introduces a 5.25-inch floppy disk drive for $390, the first of this size for microcomputers.
Three new magazines hit the stands: Byte, Computer Graphics and Art, and Dr. Dobb’s Journal of Computer Calisthenics and Orthodontia.
Other 1978 Intel introduces the 8086 chip, the start of the 16-bit microprocessor family.
January 1, 1975 The MITS Altair 8800 appears on the cover of Popula r Electronics. The article inspires Paul Allen and Bill Gates to develop a BASIC language for the Altair.
For Microsoft, 1977 marks the beginning of an official partnership between Paul Allen and Bill Gates, we hire our first official employee and the FORTRAN-80, Microsoft's second language product finally becomes available.
For Microsoft, 1978 begins with the announcement of the Microsoft COBOL-80, which conforms to the 1974 ANSI standards for 8080, Z80, and 8085 microprocessor systems.
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修改:billybear04 FROM 106.121.2.*
FROM 106.121.2.*