DCG is about 200 machines. These machines vary from individual work station class computers to large chunks of computation power. They include many support pieces of hardware. The collection of machines is referred to as the Leland environment and is also called the Leland systems.
DCG provides three large computational servers. Junior is a SGI Challenge XL machine with 16 processors and 512MB memory used for image rendering and graphics. Tree is a Sun SPARCcenter 2000/4 running Solaris 2.4 with 512MB RAM and several gigabytes of fast disk. Cardinal is a family of two large Sun SPARCstation 20/61 running SunOS 4.1.4 with 256MB RAM and several gigabytes of fast disk.
See table 
on page .
DCG helps support dial-in lines
for on and off campus computers connected to Stanford. There are several hundred modems in the modem pool accessed by a bank of phone lines answered by one number, 498-1440. This number provides service from 2400 to
14.4Kbps (meeting v.32bis standards), plus throughput up to 57.6
Kbps (with compression), SLIP service, and direct access to
SUNet. The modem pool supports almost 400 simultaneous connections. The modem pool is a joint effort in DCCS. See table on page for total modem usage. See table on page for total slip usage.
DCG provides a distributed file system with 200 gigabytes of disk space. The file system is available at several hundred mount points across campus. Backup and restore are provided. This is the main distributed file system for campus. This is accomplished with around 100 physical disk units and almost two dozen servers.
See table on page .
DCG supports a global file transfer protocol. This allows for a common disk space to place files that can be easily copied throughout the internet.
See table on page .
DCG provides email for over 25,000 accounts along with a series of machines that handle email lists. Some weeks, almost a million email messages are delivered on the DCG systems. This service is provided by several servers. Leland, the main email hub, also currently serves as many different machines including clock-e, email, imap, leland-alias-server, mail, mailhub, pop, popper, popserver, and smtp. The lists machine also serves as the email list machine and the mail list manager called majordomo.
See table on page .
DCG materializes over 25,000 accounts with full access to internet services such as email and the web. This includes, among many things, ftp, telnet, news groups, emailing lists, email, academic software bundles, third-party applications software, and public domain software bundles. Each account is provided with disk space, printing, and network connectivity.
These machines are located on the second floor of Sweet Hall and in the basement. There are about 120 large Unix workstations from the vendors of Sun, IBM, DEC, and SGI. At any one time, thousands of people are remotely logged onto these machines.
See table on page .
Some of these machines form the graphics cluster. This consists of several dozen SGI machines with a large multi-processor CPU iron. The graphics lab is capable of generating movie quality animation.
DCG provides the hardware that materializes the Network File System of several gigabytes in size. Slightly under 1/3 of the Leland accounts use this as their file system.
See table on page .
There are five laser printers on the second floor of Sweet Hall which provide free printing for every Leland account.
There are several tape drives available for account usage. We have a very large tape backup system for the distributed file system. In addition, we have several standard drive units to handle most any type of tape from most any type of system. An extra large /tmp of 600 megabytes is available.
See table on page .
There are many machines that materialize the web. The disk space for the web is stored in the AFS. Millions of URL hits happen on a monthly basis. DCG provides web service to every Leland account, hundreds of departments and groups, and machine support for web based applications. We materialize the Stanford University home web page.
See table on page .
There are three time servers providing correct distributed time for the campus infrastructure. Like the railroads, the distributed network of thousands of machines needs to be precisely coordinated in time for optimal performance.
There are five distributed security servers in the DCG. They provide a unified name space with authenticated passwords. This is the first step in a unified security policy.
See table on page .
DCG has several machines dedicated to relational databases. These machines are used to run the account database. The database classes also use these machines.
See table on page .
The physical machines that materialize the two SUL/AIR programs of Academic Data Service (ADS) and Academic Text Service (ATS) reside in the DCG. Included with these is a collection of tape devices, as well as text scanners and space in the AFS. A public text scanner is also located in the graphics lab.
Power and Wisdom are the departmental servers for several departments in the School of Humanities and Sciences, and the School of Education. Jessica is the departmental machine for Distributed Computer and Communication Services (DCCS) and hosts many Dean's email accounts. These machines, and the total operation of these machines, reside in DCG.
See table on page .
Campus wide site licensed software is distributed in DCG. Sunlight is the machine that materializes this service.
See table on page .
DCG has one of every variety of Unix box to build the public software. The distribution of these software packages is accomplished through AFS. The build is done in the build laboratory. This consists of around half a dozen machines.
See table on page
and table on page .