UNIX Version Research Articles

NASA/NSF/NCAR Computer Gateway

Over the past decade, two large computer networks have developed to serve the U.S. science community—NASA's Space Physics Analysis Network (SPAN) and the National Science Foundation's NSFnet, including connections to the Department of Defense Internet. These networks use different protocols: SPAN is based on DECnet, and NSFnet is based on TC/PIP. The different protocols make it impossible for computers on one network to communicate with those on the other without a gateway computer.The gateway computer translates one protocol into the other. Unfortunately, the number of gateway computers is small and they are overutilized. Until a standardized protocol is accepted and implemented, additional gateway computers will be needed. With this in mind, the Ocean Processes Branch at NASA Headquarters, with assistance from the Scientific Computing Division (SCD) at the National Center for Atmospheric Research (NCAR), has recently implemented a gateway between SPAN and NSFnet at NCAR. The SCD has a Digital Equipment Corporation (DEC) MicroVax II running the Ultrix operating system (DEC's version of UNIX) which can interpret both DECnet and TCP/IP protocols. This system is attached to both NSFnet and SPAN. It provides users with an internetwork mail server, file transfer capability, and remote log‐in access. No account or special access is needed on the gateway machine to make use of these capabilities.

Real-time concurrent collection on stock multiprocessors

We've designed and implemented a copying garbage-collection algorithm that is efficient, real-time, concurrent, runs on commercial uniprocessors and shared-memory multiprocessors, and requires no change to compilers. The algorithm uses standard virtual-memory hardware to detect references to “from space” objects and to synchronize the collector and mutator threads. We've implemented and measured a prototype running on SRC's 5-processor Firefly. It will be straightforward to merge our techniques with generational collection. An incremental, non-concurrent version could be implemented easily on many versions of Unix.

Unix as an office system

Abstract AT & T’s Bell Laboratories’ Unix system has both its detractors and its defenders: certainly it is complex and rather daunting to the uninitiated; but, to those in the know, it is uniquely powerful and expressive. Because of its complications, it is not the sort of software that one would normally want to let loose on an unsuspecting company as the basis of its administration system. But if the office is largely populated by computer scientists and other experienced computer users, a properly tuned version of Unix – together with some ad hoc programs – can be exactly the right tool. System Simulation Ltd is a company of this computer-orientated sort and, almost since its inception, has used Unix not only to underpin its technical programming but also for its management information, word processing, electronic mail, and general administrative work. Similar small companies looking towards setting-up computer-based administrative systems might be interested in our experience.

Software development tool for target systems and EPROM programmers within a Unix environment

A computer running under a Unix operating system is an excellent host on which to develop software for target systems which have the same type of microprocessor as the host computer. Unfortunately, facilities for preparing executable modules able to be sent to an EPROM programmer or to be loaded onto a RAM portion of target memory space are lacking in standard Unix. These facilities can be improved in any version of Unix without the need for expensive software using the set of commands presented in this paper.

Program visualization: Graphical support for software development

This article describes a prototype program visualization (PV) enviromnent that we have developed. The prototype is an umbrella in the sense that it is not targeted to support any one software development methodology. Rather, it provides basic PV tools that can be used in the service of the programmer's chosen methodology. Our system was designed to support progmming in C, although large portions ofit are independent of the software development language. The prototype itself is implemented in C and runs on a VAX 11/780 under UCB Unix Version 4.2.

UNIX as an environment for non-UNIX software development

Many of the back issues of SEN contain articles about software development environments and software tools. UNIX has historically been cited as an example of a good software development environment. For many developers still struggling with the offspring of MS-DOS, RSX-11M, OS-370 and the like, UNIX still represents a dreamed-of state-of-the-art. Many of the more enhanced environments actually sit on top of UNIX or a UNIX-like system, especially for graphics-based environments like those offered by Sun Microsystems, Apollo, and Masscomp.Pencept's business is real-time character recognition for hand-"scribbled" text. Our products run in a completely non-UNIX environment, but all of our development is done on UNIX. This presented a unique opportunity to find out how good "standard" UNIX is for developing non-UNIX products.Based on our experience, we have come to the conclusion that UNIX is a good software development environment for the kinds of applications that are traditionally run on UNIX, if UNIX is the target environment. UNIX (and most of its derivatives) do NOT address many of the more general needs of non-UNIX software engineering projects.UNIX is a powerful system, partly because it comes with a large assortment of software development tools. Some of the deficiencies and problems we had to resolve were:+ Certain UNIX and vendor software had to be modified, because it did not have all the functions we absolutely needed.+ Several UNIX utilities did poorly for this big a project.+ Some UNIX features were poorly designed for non-UNIX development.+ Some tools for our particular project are not part of UNIX.Our particular vendor is Masscomp, which competes in the high-performance graphics workstation market with companies such as Apollo, Sun Microsystems, and Digital Equipment Corporation. We believe that our experience is generally applicable to UNIX systems, regardless of vendor, and across a variety of UNIX versions (System III, System V, Berkeley 4.2, etc.)

A network of sixteen BBC microcomputers

This paper describes the implementation and services offered by a central file server and software tool facility for an undergraduate microprocessor laboratory at the University of Keele. The system consists of a central machine (an LSI- 11 23 running under the UNIX Version 7 operating system with the Newcastle Connection networking software layer) coupled to sixteen BBC microcomputers via a terminal access concentrator. Facilities to load and save programs are currently available and the latest version will allow full access to the UNIX filestore. The extensions to its facilities are discussed including the use of a Cambridge ring for the communications medium.

VT

A window package called VT has been developed for UNIX version 6 and the Heath H19 terminal. The package is written in C and is implemented entirely at the user level. Only a nonstandard system call named port is required. VT enables the user to act as if he is commanding several terminals while using a single CRT terminal. The user can make rectangular windows, each with a shell (UNIX command interpreter), and concurrently run commands in each window. All input and output for each shell is confined to its own window, so each window serves as a virtual terminal. Implementation under Version 7 and later releases of UNIX is planned.

Interfacing CAMAC to a UNIX system

In this paper the interfacing of a CAMAC system to a PDP-11/45 running UNIX version 7 is described. The main emphasis of the paper is to describe the CAMAC device driver for UNIX and to illustrate the advantages of programming the driver in the high level language C as compared with programming in assembler. It is assumed that the readership is primarily from a hardware background, and therefore we summarize some of the background and history of the UNIX system.

A message system supporting fault tolerance

A simple and general design uses message-based communication to provide software tolerance of single-point hardware failures. By delivering all interprocess messages to inactive backups for both the sender and the destination, both backups are kept in a state in which they can take over for their primaries. An implementation for the Auragen 4000 series of M68000-based systems is described. The operating system, Auros TM , is a distributed version of UNIX*. Major goals have been transparency of fault tolerance and efficient execution in the absence of failure.

A repetition construct for UNIX version 6

A repetition construct for UNIX version 6

Performance evaluation

What is experimental computer science? This question has been widely discussed ever since the Feldman Report was published (1979 [18]). Many computer scientists believe that survival of their discipline is intimately linked to their ability to rejuvenate experimentation. The National Science Foundation instituted the Coordinated Experimental Research Program (CERP) in 1979 to help universities set up facilities capable of supporting experimental research. Other agencies of government are considering similar programs. Some industrial firms are offering similar help through modest cash grants and equipment discounts. What is experimental computer science? Surprisingly, computer scientists disagree on the answer. A few believe that computer science is in flux—making a transition from theoretical to experimental science—and, hence, no operational definition is yet available. Some believe that it is all the non-theoretical activities of computer science, especially those conferring “hands-on” experience. Quite a few believe that it is large system development projects—i.e., computer and software engineering—and they cite MIT's Multics, Berkeley's version of Bell Labs' UNIX, the ARPAnet, IBM's database System R, and Xerox's Ethernet-based personal computer network as examples. These beliefs are wrong. There are well-established standards for experimental science. The field of performance evaluation meets these standards and provides examples of experimental science for the rest of the computing field.

UNIX on a micro

The earliest version of UNIX (circa 1969--70) developed at Bill Laboratories ran on DEC PDP-7 and PDP-9 computers. It was modeled on the Multics system; the operating system resulting from a joint development project undertaken in the mid-sixties by Bell Labs, MIT and General Electric (now Honeywell) which at the time it was conceived, was one of the first operating systems to be largely written in a high level language. The PDP-11 version of UNIX became operational in 1971. Dennis M Richie and Ken Thompson, joint developers of UNIX, cite its most important achievement was the demonstration that a powerful operating system for interactive use need not be expensive in either hardware of software development. They claim the main system software was developed in less than two man years. This was not done at the expense of operating facilities as the users of UNIX will testify; the system is characterised by its simplicity, elegance and ease of use.[1]