The UNIX Horizon
from the December 11, 1984 issue of PC Magazine magazine
UNIX fans have always believed their system was better than DOS. Now, with the release of the PC AT, many think UNIX will become the industry’s preferred operating system.
by Gig Graham
The software and hardware standards that have evolved from the remarkable success of the IBM PC and XT have stabilized the microcomputer industry, but at the expense of some sophistication in applications programs developed for the PC.
Now, however, the introduction of the IBM PC AT and UNIX for the PC signals a new set of standards that promises to correct the.se deficiencies and open new horizons for software developers.
In the past, PC software developers have never even considered the advantages of doing two or more things at once because DOS is not multitasking. Moreover, the DOS file system is limited to 32 megabytes, so a PC cannot function as a file server that controls, for example, a 140-megabyte Dragon disk for use by other personal computers. In addition, DOS does not handle interprocess communication, so developers have had to write their own subroutines for exchanging data among processes.
Developers also faced limits at the firmware level. The IBM Basic Input/ Output System (BIOS) interface and character generation have bottlenecked throughput and encouraged developers to bypass BIOS wherever possible or to reach around DOS into low memory to enhance performance.
At the hardware level, the PC’s slow floppy and hard disk drives have further impeded efficient I/O.
How did developers respond to this environment? Predictably, they wrote assembly language-based programs for speed, avoiding high-level languages; developed proprietary intertask communication algorithms; provided export programs for different data formats; and avoided network-based software.
Today, few applications programs that depend on DOS call for program execution — with the exception of disk I/O — and many avoid the support of firmware. As a result, PC software developers haven’t learned the advantages of depending on the operating system.
A New Direction with UNIX
The UNIX philosophy is a major departure for an industry that has evolved with DOS and the IBM PC architecture. The availability of UNIX on the XT and AT offers opportunities and solutions that are yet to be appreciated by software developers.
The UNIX kernel and most UNIX programs are small and modular, and they work together — unlike their DOS counterparts. Furthermore, independently developed UNIX applications use a common data format and can talk to each other.
UNIX encourages developers to write programs independent of a basic hardware architecture, rely on system calls to execute programs, and write in high-level languages such as C. The limitations of PC-DOS, the BIOS, and disk I/O are effectively overcome.
After all the operating systems are compared and checklists tabulated, UNIX aficionados believe that the economics of software development will make UNIX the preferred microcomputeroperating system.
Gig Graham is a cofounder and executive vice-president of VenterCom. Inc., of Cambridge, Massachusetts, which developes UNIX-based software systems.