- See Storage Area Network (SAN).
- See Source Code Control System (SCCS).
- screened twisted pair (ScTP)
- A cable where the twisted pair is screened from electromagnetic
interference by a thin aluminum screen. Not as effective as
shielding the cable. See also shielded twisted
pair (STP), unshielded twisted pair
- See Small Computer Systems Interface
- See screened twisted pair (ScTP).
- See Synchronous Data Link Control
- See Symmetric Digital Subscriber Line
- A DNS server without local files
(receiving information from the primary
server via the named.xfer process); like an NIS slave server.
- The smallest unit of physical space on a disk. Typically the
smallest unit of data that is read from or written to the
- security group
- Provide a way to organize objects
so that an administrator who has an appropriate role in the group can operate on objects
in the group.
- A process that monitors a variety of system activities, such
as the amount of disk space available, and that can generate
events or alarms based on thresholds.
- The CORBA data type for implementing
- Serial Line Internet Protocol (SLIP)
- A protocol
(RFC 1055) for connecting a host
(such as a microcomputer) to an internet
via a modem.
- A process that fulfills a request issued by a client process
and transmits a response back to the client.
- server skeleton
- Unmarshals the data associated with a request for presentation
to a method, and marshals the data returned.
- service level agreement (SLA)
- An agreement from one party to provide a specified level of
service, typically involving a maximum-allowed response time
or guarantee of service being available for a minimum time, to
another party. Service level agreements are part of any vendor
- See Standardized General Markup Language
- shielded twisted pair (STP)
- A cable where the twisted pair is shielded from electromagnetic
interference. See also unshielded twisted
- See Single In-line Memory Module (SIMM).
- Simple Mail Transfer Protocol (SMTP)
- The base
protocol (RFC 821) for exchanging electronic mail over a
network. See also Extended Simple Mail
Transfer Protocol (ESMTP), Multipurpose
Internet Mail Extensions (MIME), NeXTMail.
- Simple Network Management Protocol
- A base
protocol (RFC 1157) for monitoring and managing hosts on
a network. See also Management Information
- Single In-line Memory Module (SIMM)
- A small plug-in card containing memory chips for a workstation
or personal computer.
- The ORB component which assists an
object adapter in passing requests to particular methods. It
is specific to an object and an interface.
- See service level agreement (SLA).
- The secondary NIS servers in an NIS domain.
- See Serial Line Internet Protocol
- Small Computer Systems Interface (SCSI)
- Pronounced "scuzzy," SCSI is a parallel interface standard
used by Apple Macintosh computers, PCs, and many Unix systems
for attaching peripheral devices to computers. SCSI interfaces
provide for faster data transmission rates (up to 80 megabytes
per second) than standard serial and parallel ports. In addition,
you can attach many devices to a single SCSI port, so that SCSI
is really an I/O bus rather than simply an interface.
- See Simple Mail Transfer Protocol
- See Synchronous Network Architecture
- See Synchronous Network Architecture
Distribution Services (SNADS).
- See Simple Network Management Protocol
- See Synchronous Optical Network (SONET).
- Source Code Control System (SCCS)
- A suite of utilities to administrate source code such that
only one person can change any given file at any given instant.
Provides audit trails.
- The historical term for electronic junk mail, or unwanted
messages in email or USENET News. See also Unsolicited Commercial Email (UCE).
- The speed of various technologies can best be shown by the
Portions of this table taken from the Keane
(New Hampshire) Public Library database.
||3-foot garden path
||3.6 x T3
||~1-mile wide highway
||4 x OC3
||~4-mile wide highway
|4 x OC12
|~16-mile wide highway
||4 x OC48
|~64-mile wide highway
- See Structured Query Language (SQL).
- A last in, first out data structure. See also
- The process of configuring a host to a known state (for
example, from tape or a preconfigured host), to speed up the
- Standardized General Markup Language
- A generalized format for marking up documents, originally
created by the United States government. One of the more common
subsets of SGML is HyperText Markup
- state database
- A database containing the state of each metadevice, stored
in a dedicated (and non-metadevice) disk partition. See also
- Storage Area Network (SAN)
- A network where a small number of computers share a large
amount of data, usually within a single server room, where
performance is critical. Examples of SAN protocols include Fiber Channel and the Small
Computer Systems Interface (SCSI).
- See shielded twisted pair (STP).
- A method of writing data to multiple disks, interleaving
blocks on different disks to increase performance. (Performance
increases generally require multiple disk controllers.) A
logical grouping of multiple physical disk partitions. See also
concatenated stripe, Disk Suite.
- stripe width
- The width of, or number of partitions in, a
- Structured Query Language (SQL)
- An industry-standard language for performing queries against
- A local procedure corresponding to a single operation that
invokes that operation when called.
- A metadevice attached to a mirror.
- A group of machines that share information and resources. A
subsection of a network.
- Registering resources to a group, so that operations on a
group are applied to all subscribers.
- Sun Remote Procedure Call (SUNRPC)
- The Remote Procedure Call (RPC)
structure developed by Sun for communication between clients and servers.
For example, NetInfo uses RPC to
- See Sun Remote Procedure Call (SUNRPC).
- A special reserved block on disk that contains the detailed
structure of the file system,
including the block size, frag size, and inode
- See Switched Virtual Circuit (SVC).
- Swap space is a place on your disk(s) where your processes
go if you run out of physical memory. It is part of the virtual
memory system of all Unixes, allowing you to have more process
memory than phsyical memory, if you need it. If you run out of
swap space, you will be unable to create more processes.
Solaris uses an "eager" swap algorithm - it reserves space when
it creates a process, so even if you never ever use it, you
have to have "enough" in your system, just in case. So, what
At the least, swap space should be as large as the RAM in the
system. In an ideal world, all of our machines have plenty of
memory and this never happens. In reality, something as simple
as a page-compile, which launches a whole new JVM process, can
put you over the edge. Thus, it should probably be set at
~1.5x the physical memory. A good rule of thumb from the 1990s
was that swap should be twice physical memory.
Here are some tools you can use to see what's up with your swap
- swap -s
- This will show you what's available, and what is
- vmstat -S 5
- This will print out system stats every 5 seconds. If
you are moving things in and out of swap you will see
non-zero numbers in the "so" and "si"
in the "page" stats and you'll probably also
see "free" in the "memory" stats
going very low.
- Network hardware that routes packets
or cells (either ATM
or voice) based on the address of the virtual circuit.
- Switched Virtual Circuit (SVC)
- A virtual circuit in an ATM network
established dynamically via software.
- Symmetric Digital Subscriber Line (SDSL)
- A symmetric high-speed digital network connection, usually
between a home or small business and a telecommunications
vendor, providing an always-up direct connection to an Internet Service Provider (ISP). The
upstream (from the user to the ISP) and downstream (from the
ISP to the user) speeds are identical. See also Asymmetric Digital Subscriber Line (ADSL),
Digital Subscriber Line (DSL).
- Synchronous Data Link Control (SDLC)
- A data protocol spoken between the DISOSS
mail system on the IBM 3090 mainframe
and the Enterprise Mail Exchange (EMX)
- Synchronous Network Architecture (SNA)
- IBM's network architecture.
- Synchronous Network Architecture Distribution
- The distribution protocol, handling delivery and verification,
for Synchronous Network Architecture (SNA).
- Synchronous Optical Network (SONET)
- An ANSI standard to connect telephone
switches at 155 Mb/s speeds (OC3).
- See system administrator.
- system administrator
- The godlike being who keeps your system running. Responsible
for everything involving your system and the network it's on,
including but not limited to managing your account (creation,
modification, closure, deletion), your workstation, your subnet,
your routers, the system-wide hosts table, the mail subsystem,
all mail aliases and groups, keeping time synchronized across
the network, the news subsystem, the printer subsystem, any
applications you use--basically, the person who keeps everything
working smoothly and seamlessly.