Table of Contents Host Configuration: Workstation Administration

Host Configuration: Workstation Administration

Walter C. Wong
Computing Services
January 7, 1993

SECTION 1 Introduction

1.1 Initial Software Requirements Specification
The Initial Software Requirements Specification (ISRS) is the first step in the requirements analysis process. The ISRS lists the requirements of a particular Computer System Item (CSI), including functional, performance, and security requirements. The ISRS also provides usage scenarios from a user, an operational and an administrative perspective.

The ISRS discusses implementation detail only if it contributes to feasibility or cost.

This document will be identified as Host Configuration: Workstation Administration Initial Software Requirements Specification. Future references to ISRS refers to this document unless otherwise noted. The CSI referred to in this document, unless otherwise stated, is Host Configuration: Workstation Administration.

1.2 Host Configuration: An Overview

The Host Configuration project addresses issues of workstation management. In defining the requirements for Host Configuration, three separate aspects are discussed:

1.3 Workstation Administration

Workstation administration emphasizes the distributed management of system software. That is, the operating system software and the software that the workstation needs to accomplish any specific service. This document does not explicitly concentrate on the management of third-party and locally developed software. Tools such as depot [COLYE92A] can be used to address this issue. [COLYE92B] describes the way depot is used in an AFS environment to management the software environment.

This project does not discuss the issue of backing up the local disk of individual workstations. The reader of this ISRS should assume that there is no important data on the workstation or an external backup mechanism is available. Backup issues are addressed by the Andrew II Backup and Archiving Project.

Another aspect that is not directly addressed is account management. Password file distribution and configuration will be treated as any other file in the CSI. The actual process of building of a central password is outside of the scope of this document.

This document will only discuss Workstation Administration. At this date, a formal discussion of docking and performance management is somewhat premature. These two aspects do not form a CSI by themselves. Rather, they are concepts and guidelines that are to be introduced and integrated with a CSI after an initial functional requirement analysis.

1.4 Contact Information

Please feel free to contact the author with any comments or criticisms. The author can be reached at the following address:

Walter C. Wong Internet:
UCC 179 phone: (412) 268-8514
Computing Services FAX: (412) 268-4987
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213-3890

1.5 Revision History

September 24, 1992 - First public release
December 7, 1992 - First reviewed revision

1.6 Acknowledgments

The author would like to thank the following people for their helpful comments on the document: Bill Arms, Wallace Colyer, Tracy Futhey, Alan Hastings, and John Lerchey. Many thanks are also go to Julie Jenson for proofreading and designing the format of this document.

SECTION 2 Applicable Documents

2.1 Reference Documents
The following documents form a part of this document:

[COOPE92] Cooper, Michael, A. "Overhauling rdist for the `90s." LISA VI Proceedings. October 1992. pp. 175-188.
[OSF91A] Distributed Management Environment: Rationale. Open Software Foundation. October, 1991.
[OSF91B] Distributed Management Environment. Slides from the DME presentation. 1991.
[HOWEL92] Howell, Paul; Killey, Paul, and Kuno, Harumi. Client Syncing of Local File Space. Computer Aided Engineering Network, University of Michigan. 1992. DRAFT.
[ROSEN92] Rosenstein, Mark, and Peisach, Ezra. "Mkserv - Workstation Customization and Privatization," LISA VI Proceedings. 1992. pp. 89-95.
[SMITH89] Smith, Susanne, and Quarterman, John S. "White Paper on System Administration for IEEE 1003.7,";login:. Volume 14, no 4. July/August 1989. pp. 17-23.
[SHAFE85] Shafer, Steven, and Thompson, Mary. The SUP Software Upgrade Protocol. School of Computer Science, Carnegie Mellon University. 1985
[WONG92] Wong, Walter C. The Andrew Workstation. Computing Services, Carnegie Mellon University. 1992.

2.2 Informational Documents

The following provide some background or additional material that is relevant to this document:

[COLYE92A] Colyer, Wallace; Held, Mark; Markley, David, and Wong, Walter. "Software Management in the Andrew System." AFS User's Group Proceedings. July, 1992.

[COLYE92B] Colyer, Wallace, and Wong, Walter. "Depot: A Tool for Software Management," LISA VI Proceedings. 1992. pp. 151-160.

[FURLA91] Furlani, John. "Modules: Providing a Flexible User Interface." LISA V Proceedings. 1991. pp. 141-152.

[OSF92] Distributed Computing Environment: An Overview. Open Software Foundation. January 1992.

[OSF91C] File Systems in a Distributed Computing Environment: A White Paper. Open Software Foundation. July 1991.

[HAYES92] Hayes, Frank. "The System Administration Squeeze," UnixWorld. October, 1992. pp. 67-70.

[KOHL92] Kohl, John T.; Neuman, B. Clifford, and Ts'o, Theodore Y. The Evolution of the Kerberos Authentication Service. August 1992. Available via anonymous ftp from in /pub/kerberos/doc.

[SATYA85] Satyanarayanan, M.; Howard, J. H.; Nichols, D. A.; Sidebotham N., and Spector, A. Z. "The ITC Distributed File System: Principals and Design." Proceedings of the 10th ACM Symposium on Operating System Principals. 1985.

[ZAYAS88] Zayas, Edward, and Everhart, Craig. Design and Specification of the Cellular Andrew Environment. ITC Technical Report CMU-ITC-070. August 2, 1988.

2.3 Miscellaneous Documents

The following documents were used to create the template for the ISRS:

Software Requirements Specification, Data Item Description 08. Office of Safety, Reliability, Maintainability and Quality Assurance. NASA. Version 3.0, October 15, 1986.

IEEE Guide to Software Requirements Specifications. IEEE Std 830-1984. Institute of Electrical and Electronics Engineers. February 10, 1984.

SECTION 3 Project Overview

3.1 The Problem
The problem of distributed workstation administration is not just a problem of numbers. While large numbers of workstations do make administration difficult, many other issues complicate the process. For example, many machines are often owned by people who simply want them to work but do not want to spend the resources in order to keep them working. In this case, workstation maintenance may be thrust upon graduate students or their commercial counterparts who may lack the technical expertise to manage the machines. As a result, the bulk of the work may be dropped upon some unlucky individual or organization with the technical expertise, or the work may simply be dropped. The situation, then, deteriorates slowly until immediate assistance is required. The insidious aspect of system administration is that the system can appear to be functioning properly, but, unless the proper tasks are done, one small event (disk crash, break-in, etc.) can lead to catastrophic failure.

To further complicate matters, individual vendors have begun to offer their own system administration tools. Examples of these tools include SCAMP and FullSail from DEC, netinfo from NeXT, and SMIT from IBM. Currently, these systems do not interoperate with each other or provide a common interface to their functions. Many of these tools come with unreasonable limits, such as limits to the maximum number of machines, or limits that require the all system management operations to go through the tool. Thus, most of these tools cannot interoperate with the existing management tools that large sites already use.

3.2 The Rationale

The Andrew system already has a working workstation administration system, which will be described in more detail in section section 4.1 on page 19. It is conceivable that the current system could continue its forced evolution and continue to function for many more years. However, there are some significant shortcomings with the system that make it worthwhile to start fresh and examine what was done right and what should be fixed. Furthermore, there is a growing concern that the future direction of system administration tools and facilities will conflict with the Andrew system. This document and this project should help draw attention to our environment and, hopefully, head off any detrimental standards or practices.

3.3 The Goal

The ultimate goal at the completion of CSI is to have a system that allows us to manage the system software and files of a potentially infinite number of workstations with a relatively small technical staff. The technical staff would provide a default workstation configuration that acted as a foundation on which further customization could occur. Each client machine would be configured to optimally use the resources available and customized to meets its owner's needs. At the same time, the system staff would be able to upgrade and update software transparently to the user.

While it would be ideal if each user could reconfigure their environment dynamically, it does not seem to be feasible given the technology widely available. For example, it would be desirable for two users, using the same machine at the same time, to have environments tailored to exactly what they wanted. Although John Furlani's Module system [FURLAN91] provides a mechanism to accomplish some this, it would be rather awkward to integrate it with our software management system. At this time, reconfiguring workstations with different software packages appears to be the most practical approach.

Figure 1 The Layered Approach

It is believed that the current Andrew model can achieve this goal, to a certain extent. This model can be described in two ways. The first approach is to describe the model as layered, as shown in Figure 1. The core functionality of the system is provided by a small, technical, central staff. They also provide general and commonly used services. The next layer is the departmental administrators. Departments and organizations may have special configurations and configurations that span their entire computing community. This layer allows them to make custom changes without having to duplicate the work already done by the central staff. The final layer is the individual workstation. This allows for machine specific changes to be incorporated into the management system.

The Andrew model can also be thought of as a pipeline through which software flows, as illustrated in Figure 2. The central administration provides the main software feed. This feed is taken by the departmental administrators and modified or combined with any additional departmental services and software and then passed on to the local workstation. The local workstation then has the opportunity to make its own customization and to incorporate software and services that are specific to it.

Figure 2 The Administrative Pipeline

The model does not constrain the feeds and layers to only central, departmental, and local. Any number of feeds or layers can be introduced after the central layer. For example, in our environment, an additional college tier could be added between the central administration and the departmental administration. The central layer is presumed to always be there as there is probably some organization that will be providing the base systems. Also, a local layer may or may not exist, depending on if there are any workstation specific changes required.

The Andrew model provides a default management environment where software is automatically installed and updated. This environment also has the flexibility to allow departmental or local administrators to customize that environment. Those with technical resources can use those resources to fine-tune the environment rather than build a custom environment from scratch to match their needs.

The current Andrew model has been built around a strong central administration, and individual workstations either use the system or do not use it. However, the model doesn't preclude the ability to lessen the dependence on the central administration. The model allows the possibility for a departmental or local administrator to merge the output of two central administrative feeds. In general, it is doubtful that this will be necessary.

The broadest goal of the CSI is to provide a system that performs and allows for:

of software and files on the local disks of workstations in a manner that is:

These topics will be discussed in more detail in the Functional Requirements, in section section 6.1 on page 31.

Because of the variety of computer systems and implementation philosophies, it is very possible that a single solution is not available or even ideal. If this is determined to be the case, then CSI specific to the implementation flavor will be chosen or developed.

SECTION 4 Related Systems

The following sections provide a quick overview of several known systems for workstation administration. It is strongly recommended that the reader review the references and not rely solely on the summaries. The author of this document only has first hand experience with a few of the systems discussed in the section.

4.1 Andrew


The Andrew System includes approximately 600 workstations at Carnegie Mellon University. These workstations encompass individual workstations for faculty and staff, publicly available machines in computer clusters, and service workstations that perform a variety of tasks such as providing UNIX access or running the mail and backup systems. This management system uses a set of tools, package and mpp, for maintaining the workstations. The system is commonly referred to as just package.

Package, by itself, is very simple. Package ensures that files and directories on the local workstation match those on AFS [SATYA85], a distributed file system present on all Andrew workstations. If they do not match, package replaces the local file with the one from AFS. If the file does not belong then package will remove that file.

Without mpp, it would be quite difficult for customization to occur. Mpp is a macro preprocessor that creates the configuration files that package uses. Depending on what variables are defined, mpp will generate different package files from the same configuration files.

The benefits of the system include:

The main drawbacks of package are:

The Andrew System also tries to maintain a clear separation between the operating system and local and third party software. Local modifications to the operating system, such as to programs like /bin/login, are copied from /usr/local to /bin by package. All third party and local software are kept in /usr/local which is managed by a tool called depot [COLYE92A]. The software management process using depot and other tools is described by [COLYE92B].

4.2 Software Update Protocol - SUP


SUP is used by the School of Computer Science and the Department of Electrical and Computer Engineering at Carnegie Mellon to maintain over 1,000 workstations. As with many of these packages, the purpose of SUP is to ensure that multiple machines will automatically have the same software base.

SUP separates software into different collections. Each collection is a logical "unit" of software. For example, all the files and directories needed for gnu-emacs would form the gnu-emacs collection. To distribute the collections, SUP takes a client/server approach. For each collection, there is a SUP server that exports it.

Some benefits of SUP include:

The limitations of SUP are:

4.3 mkserv


mkserv maintains over 1,000 workstations in the Athena environment at MIT. Athena recognizes that managing many machines that are identical is not that hard a task. The difficult task is trying to manage multiple machines and allow customization to occur.

mkserv uses a configuration file to determine what services a particular machine should have. After mkserv determines what services are on the machine, all of the files required for the service to function are copied to the local disk.

The benefits of mkserv include:

Some limitations of mkserv are:

4.4 Synctree


Synctree used at the University of Michigan's College of Engineering, specifically the Computer Aided Engineering Network, to manage over 1,000 workstations. The management paradigm does not differ much from the other packages; there is a master copy of software on a distributed filesystem and synctree makes sure that what is on the local disk matches the master copy. It is believed that this synctree is different than the one used by mkserv.

The master copy on AFS for synctree is separated into different sections known as templates. There is a base template, called GENERIC, that loads the basic operating system for any given system type, such as SunOS 4.1.1 for Sparcstations. Since all workstations are not alike, the next level creates a "class" distinction for each workstation. Each workstation can belong to several classes with one class having precedence over the others. The classes give a group identity and thus certain group characteristics to the workstations. For example, a workstation could have the class of being a STAFF workstation or a LAB workstation. In addition, there is the BETA class that uses software being tested. Finally, there is the workstation specific template directory. That directory contains files that are specific to the workstation, such as /etc/fstab.

The benefits of synctree include:

Some drawbacks of synctree appear to be:

4.5 OSF Distributed Management Environment

[OSF91], [OSF92]

The Open Software Foundation's Distributed Management Environment strives to unify network and system administration. Although the DME is still currently under development, if it were adopted by all vendors it would provide a consistent management environment across multiple platforms.

The DME has the potential to create a standard mechanism for initial software installation. This is the case when one has just purchased a workstation and there is nothing on the disk. Right now, each vendor has their own installation procedure and many management tools, such as package, require that the vendor's installation tools are used until the point that the local management can take over. Often this transition is not very smooth and requires modification to the vendor's installation system. Other times, the management system is restricted by the initial load system. For instance, while SunOS offers an initial network installation procedure, it makes it difficult to do more than one installation at a time.

Some architectural problems of the DME deserve some attention. First, there is the sheer bulk of the system. It is quite possible that in order to use the DME, it is necessary for one to have all the supporting infrastructure, such as the DCE. This may significantly limit the number of machines that can use it, as well as greatly increase the time and resources required to install and use the DME. Secondly, the OSF process makes the DME more vulnerable to the problems that occur when anything is designed by committee: a product that can do everything, but can do nothing well.

Two aspects of the DME apply to this document: the "object-oriented" management environment and the software distribution and installation component. The only references that are currently available are more marketing than technical. As a result, the two following sections are mostly summaries of the two references listed above.

4.5.1 The Object Oriented Management Scheme
The management model for tracking and maintaining the workstations in the management environment takes an object oriented approach. The OSF defines an object in this context as "the consolidation of data and operations into one entity - a managed object - which represents the resource or service to be managed." Thus, all management operations are done through communications with the management objects.

The implementation of this system involves creating a three-tiered approach. At the bottom of the tier, is the individual node or workstation. This level allows for any individual customization and configurations that may occur. This is also to designed to make the DME useful for smaller sites. The second tier is the "cell" level. As with DFS [OSF92], this is a management abstraction to allow different organizations to have independent management domains for their group of workstations. This will allow management operations to be made available to entire groups of machines. The final tier is the "enterprise" level. This tier does not access the individual workstations but rather sends management operations to the cell.

4.5.2 Software Distribution and Installation
The information included below is an excerpt of the selection rationale for the software distribution and installation component:

4.6 Macintosh/PC Systems

Workstation administration software for the Macintosh and the PC lag behind the tools available for UNIX systems. Macintosh systems mostly follow the "push" mechanism and are more orientated around network monitoring of Macintosh systems rather than a full blown software distribution mechanism. However, there appears to be a version of rdist, known as revRDIST for the Macintosh. Furthermore, more and more file synchronization tools are being written as a result of the Macintosh portable computers. This may lead to better workstation administration tools.

The only PC system found at this point is a product that has yet to be released. This program does software distribution based on `cloning.' That is, it allows for a single configuration to be identically copied to multiple machines.

Investigations into the Macintosh/PC world are continuing as more systems appear and this document will be updated to reflect these changes.

4.7 DEC setld

setld from DEC is not a workstation administration tool in the true sense. It is more of a software distribution and installation mechanism. It is included in order to point out some potential pitfalls.

Software using setld is compartmentalized into different software subsets. Each subset consists of the following items:

The system is capable of installing, removing, verifying and listing the software on the system. Two drawbacks exist in the system. First, it is quite complex and the documentation for generating the subsets is not very clear. Second, the script files are overused because it is much easier to do the work in the script than elsewhere. For example, often dependency checks are done by the script rather than by the provided mechanism. Finally, the philosophy behind this is geared towards singly managed systems. That is, it is expected that one would run setld on each client. As a result, it is very difficult to use setld to install software for a group of machines unless they are all identical, since setld in the scripts may configure the software packages to the workstation that setld is running on.

4.8 rdist


rdist is a rather old, and in use, UNIX software distribution tool. The reviewed version, however, is a new version, version 6.0, from University of Southern California.

rdist is a file based distribution system. Files to be distributed are "pushed" from a central server to all the clients. The files that are distributed are described in a single configuration file. The configuration file specification is not as bad as package, as wild cards are allowed and mode, owner, and group information is taken from the file rather than having to be specified explicitly.

The benefits of rdist include:

The problems with rdist are:

4.9 Summary

The two different distribution approaches, "push" versus "pull," illustrate different distribution mentalities. The "push" method is an authoritarian, "dictatorial" approach in which the configuration of the client workstations must "follow and obey" the directions of the server doing the "pushing." On the other hand, "pull" is a much more laissez-faire approach where clients request software from the servers.

Each model has its benefits and drawbacks. For example, the "push" model is best for machines whose configuration must remain consistent and not change unless someone explicitly changes. This is quite useful for machines providing services used by the community.

The "pull" model, however, is much more scalable as the servers have much less work to do. This model assumes that if something goes wrong, someone will contact you to fix it rather than you having to go out and fix it immediately. Also, in the case that a distributed filesystem is present, the distribution mechanism tends to lean towards pulling from the distributed filesystem.

Items to be reviewed in the next revision include the following items: Tivoli's WIZdom, POSIX 1007.2, HP's Software Distribution Utilities, and Radar.

SECTION 5 Scenario Descriptions

The following sections describe typical use scenarios for the CSI. This section is not meant to be a comprehensive list of all the functionality available. Instead, this section should provide the reader with a general understanding of how the CSI will be used.

5.1 User Scenario

The CSI should be transparent to the user of the workstation. "User" in the context of the CSI refers to the workstation administrator. The workstation administrator may be the owner of a single workstation or the person in charge of multiple workstations. The workstation administration may also be a group of people responsible for any number of machines.

To the user, the CSI will provide a functioning system where the following software can be automatically updated:(2)

If the default environment is not sufficient for the user, then customization can occur to the workstation configuration. These customization could consist of any or all of the following items:

The mechanisms for using the CSI should be similar, if not identical, between the departmental and local workstation administration, with the exception that the departmental administrators may provide additional "library routines" for their local users that are not provided by the central administration.

Ideally, direct editing of configuration files should not be required. Instead, there should be a user interface. See section section 6.1.13 on page 35 for more details on the user interface. Novice users may prefer to use a user interface while experienced users may want the flexibility of editing (or even writing programs to edit) the configuration files directly.

Once a configuration is created, the user should not have to change the configuration in response to central changes. For example, central administration should be able to upgrade the operating system without forcing users to change their configuration files. However, if a user has installed an application locally that is incompatible with the newer version, then a configuration change may be required. In essence, the user has administrative control over the aspects that he wants control over and delegates responsibility of the aspects that he does not want to deal with to other administrators.

5.2 Operational Scenario

No direct operations support should be required for the CSI.

5.3 Management/Administrative Scenario

This scenario deals with the central administration. The central administration is responsible for providing the default services and environment from which all customization is based.

The process that the central administration would have to proceed is enumerated as follows:

1. Install the operating system on a workstation.
2. Install the CSI on the workstation. The first two phases are to "bootstrap" the CSI. In the event that the CSI was already present then the first two steps would not be required.
3. Load the operating system into the CSI for distribution. The involves loading the entire operating system as shipped by the vendor. In general, if an operating system can be shared between multiple models of the same workstation family (e.g. DEC 2100, 3100, 5000/1xx, 5000/2xx) with only minor changes, the same base should be used. See section section 6.1.12 on page 35 for more details.

After this step is completed, the operating system should be distributable by the CSI.

4. Install the OS layered products into the CSI.
5. Install third party and locally developed software into the CSI. This includes installing all the appropriate software licenses. See section section 6.7 on page 40 for more details on licensing.
6. Install site customization and basic services into the CSI. These include site specific configuration items as well as site independent services that require modification to base configuration files. Examples include pointing the CSI to the appropriate password file and creating the proper directory structure and inetd.conf to allow anonymous FTP.
Ideally, no further action would be required by the central administration to maintain the workstations. Day to day maintenance would be done automatically or on each reboot. For example, new password files would be distributed by the CSI without any central intervention.

Unfortunately, software rarely remains static. While the operating system may not change very often, new application software and new versions appear, and old unused software and older versions should be removed. Removal, is by far, the easiest part. Given that the CSI compartmentalizes the software, removal is just removing the pointer to the collection and then waiting for that removal to propagate to all the client workstations. Installation can also be as simple as installing into the CSI and waiting for the version to propagate to the clients. Compartmentalization also aids in the "backing out" process. As long as previous versions are kept, broken software can be easily removed from the production environment and previously working versions can be restored.

It is important to point out at this time that the CSI server need not be a real machine. In the current AFS environment, the directories in which files are stored are not directly accessible by the server machines, unlike NFS. Installation of software into AFS involves using a client to store the files onto the AFS server. If the CSI uses a distributed filesystem, such as AFS or DFS, as a method of distribution, then the distributed filesystem should be considered the CSI server.

SECTION 6 Requirements

This section provides a list of requirements that are needed for the CSI. They are classified as either mandatory or highly desirable.

6.1 Functional Requirements

6.1.1 Initial Installation
It is highly desirable that the CSI:
If this requirement is implemented by the CSI, then it is mandatory that the CSI:
If this requirement is implemented, then it would be highly desirable for the CSI:
This requirement is not mandatory as there is no standardization in this field yet. Each vendor and each operating system all have different methods of dealing with this issue.

6.1.2 Automation
It is mandatory that the CSI:
This assumes that working system is already in place. It is not a requirement that the CSI can automatically determine what configuration the user wants.

6.1.3 Software Installation
The installation of software in the CSI comes under two forms: installation for a single workstation, and installation for multiple workstations in the CSI. In the installation of software for a single machine, one has the option to use the vendor install scripts and tailor that application for the specific machine. However, installing for a group of machines requires the installer to load all components of the collection, make any global configurations and then put in the "hooks" necessary for the software to run on all of the workstations receiving the software. The multiple machine installation assumes that the group of machines want the software configured the same way (or there really aren't any configuration differences that matter).

As discussed in section section 4.9 on page 26, many vendors avoid the multiple workstation installation problem by simply distributing the "raw" form of the collection to each workstation. This is not acceptable as it violates the simplicity requirement in section 6.1.11 on page 35.

It is mandatory that the CSI:

It is highly desirable that the CSI:
6.1.4 Removal
It is mandatory that the CSI:
The system manager must not need to go to each workstation in the CSI to remove software from them.

6.1.5 Workstation Maintenance
It is mandatory that the CSI:
6.1.6 Configuration Management
It is mandatory that the CSI:
It is highly desirable that the CSI:
6.1.7 Scalability
It is mandatory that the CSI:
6.1.8 Distribution
It is mandatory that the CSI:
6.1.9 Transport
It is mandatory that the CSI:
This requirement is subject to change as Carnegie Mellon's network configuration changes.

6.1.10 Documentation
It is mandatory that the CSI:
6.1.11 Simplicity
It is mandatory that the CSI:
It is highly desirable that the CSI:
The importance of simplicity can not be understated. By having multiple modular tools, one avoids ending up with an unmanageable and difficult to understand "kitchen sink" system.

6.1.12 Auto-Configuration
It is mandatory that the CSI:
In general, if the operating system Fizzlebrot 4.3 supports workstation models FizzBang 6000 AXP and FizzBoom IIe then the CSI must only need one copy of FizzleBrot 4.3 even if the FizzBoom has devices with different major/minor numbers and if the X server is different between the models. What must occur in that the CSI determines which workstation model it is and then makes sure the appropriate file gets distributed to the workstation.

6.1.13 User Interface
It is highly desirable that the CSI:
If a user interface is present, then it is mandatory that the user interface:
6.1.14 Distributed Filesystem Interaction
This section assumes that a distributed filesystem is available on client CSI workstations. This section also assumes that a file exists either on the local disk of a workstation or the file can be a pointer (e.g. a symbolic link) to a file on the distributed filesystem.

It is mandatory that the CSI:

6.1.15 Shareability
In large organizations, there may be many independent computing facilities that wish to remain administratively independent of each other. There may also exist computing facilities that wish to have administrative control in some areas but relinquish control in others.

It is mandatory that the CSI:

6.1.16 Full Workstation Functionality
It is mandatory that the CSI:

6.2 Performance Requirements

There are many factors complicating the timing requirements. For example, if a distributed filesystem is used, then the performance of the CSI will depend on all the factors that complicate the performance of a distributed filesystem, such as the performance of the network and the performance of the fileservers. Also, the size and number of software collections will also have a significant impact on performance.

In order to provide some concrete goals, some specific numbers will be provided. In the event that design and/or implementation proves these numbers to be unfeasible, then a more realistic number will be chosen, based on the data provided.

It is mandatory that the CSI:

Completion time is very important for the client CSI workstations as the CSI may have a significant impact on the usability of the client workstation during execution. Thus, the sooner the CSI completes, the sooner the user may continue using the workstation. Second, the less time the CSI executes, the smaller the chances are that something else will go wrong, such as network or server failures.

6.3 Environmental Requirements

The environment is assumed to be an environment with a large number of heterogenous workstations. Environments with a smaller number of workstations should be able to use the CSI without undue overhead, though it is not required. Large is defined as any number over 50. Small is any number under 5.

It is assumed that the workstations will be connected via a relatively high speed local area network, such as Ethernet. There must be provisions, however, to offer basic functionality of the CSI to machines connected via low bandwidth connections, such as SLIP. This issue will be addressed in detail in the Docking component.

The Andrew II project is assuming a OSF DCE/DFS [OSF92] based environment. We expect to have over 4,000 workstations by the year 2000.

It is very unlikely that the CSI will become the standard campus environment. Many organizations may adopt the CSI and remain administratively separate, as discussed in Section section 6.1.15 on page 36, but it is quite possible that many of the large organizations will not see the need nor be able to justify the expense of switching to a new system when their existing systems already suit their needs.

It is mandatory that the CSI:

6.4 Database Requirements

It is mandatory that the CSI:
This information must be detailed enough to determine the location of the original copy of the file and any other "important" fields. (An important field is vaguely defined at this stage to be a field relevant to any workstation administrator.)

6.5 Quality Factors

The subsections below specify the quality factor requirements of the CSI, to the extent possible, in quantitative terms.

6.5.1 Reliability Requirements
It is mandatory that the CSI, the event of failure:
6.5.2 Portability Requirements
It is mandatory that the CSI:
It is highly desirable that the code for the CSI:
6.5.3 Efficiency Requirements
It is highly desirable that the CSI:
An excessive consumption of resources is considered to be one where no other action can be performed on a multi-tasking system while the CSI is running, i.e. CPU time, memory usage, disk space usage.

6.5.4 Usability Requirements
It is mandatory that the CSI:
A novice user would most likely be the user that would only services predefined by central or local administrators. An expert user would be the ones who actually define these services. For example, a novice user would simply say that he wants his workstation to be an anonymous FTP server. An expert user, on the other hand, would be able to modify this service such that he could use a different FTP server.

Note that the term user is used in the same context as described in section section 5.1 on page 27.

6.5.5 Maintainability Requirements
It is mandatory that the CSI:
6.5.6 Reusability Requirements
Components in the CSI are not required to be reusable outside of the CSI. The CSI, however, is envisioned to be a set of inter-operating programs and not a large monolithic entity.

It is mandatory that the CSI:

6.6 Security Requirements

It is mandatory that the CSI:
It is highly desirable that the CSI:

6.7 Licensing Requirements

The issue of software licensing is not, specifically, tied into the area of workstation administration. Ideally, the licensing of software should be transparent to the distribution mechanism. However, this is not always the case. Licensing can affect the way software installed, tracked, and removed.

There are three main forms of licensing:

Software distribution in the first two items doesn't have that much to worry about. Any distribution mechanism can handle magic number licensing and floating licenses. The more difficult is the last item. In this case, the distribution mechanism has to know whether or not the machine is authorized to receive and install the software. When the license expires and is not renewed then the CSI would have to have the software removed. Finally, there would also need to be a mechanism to track usage in order to determine whether or not it is worth extending the licenses.

SECTION 7 Glossary

The following are the acronyms and terms used in this document.
AFS Andrew File System - A large scale distributed filesystem from the Transarc Corporation.
Collection A software package. A collection is a set of one or more files belonging to the same software package.
CSI Computer System Item - The Computer System Item is the resulting software and/or hardware which meets the requirements as described in the appropriate ISRS. CSI, in this document, refers to the system for workstation administration.
DCE Distributed Computing Environment - The basis for distributed computing from the OSF.
DFS Distributed File System - Depending on context, this may refer to distributed file systems in general or refer, specifically, to the OSF Distributed File System.
ISRS Initial Software Requirement Specification - See section section 1.1 on page 9 for more information.
OS Operating System - The programs and files that provide the software which the computer needs in order to function.
OSF The Open Software Foundation.


We will henceforth refer to any Intel 80x86 based systems as PC systems.
Update includes installation of new software, removal of old software, in addition to new versions of currently available software.
This does not mean that the graphical user interface is required to look identical across all platforms. For example, a Macintosh interface to the CSI would like a typical Macintosh application; the Windows interface would look like a Windows application, and the X11/Motif interface would resemble a Motif program. Regardless of superficial differences, the underlying design and layout can be the same or similar enough between all platforms for users to easily migrate from one architecture to another.
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