aliasing- The ability of a shell to assign a name or an alias to a set of commands and to use the alias to execute the commands.
authentication- A method to restrict access to specific users when accessing a remote system.
authorization- A method to restrict the operations that a user can perform on the remote system once the user has gained access (been authenticated).
Berkeley Software Distribution (BSD)- The version of the Unix operating system developed by the University of California at Berkeley.
Bourne shell- A version of the Unix shell developed by Steven Bourne from AT&T Bell Labs. It is referred to as sh.
C shell- A version of the Unix shell developed at the University of California at Berkeley. It is referred to as csh.
client- A networked computer system that uses services provided by a server.
client/server- An operation model used by computer systems where services are centralized on a server and accessed by one or more clients via a network.
Cocoa- Cocoa is what used to be called "yellowbox" in previous releases of Rhapsody and OSX. The Yellowbox is basically the main development platform for OSX. It includes Java, ObjC and C++ coding availability.
crontab files- Files stored under /var/spool/cron/crontabs that specify commands to be executed along with a time and frequency of execution. Commands can be executed daily, weekly, or monthly at any time of the day. A crontab entry consists of six fields separated by spaces or tabs. An asterisk (*) is used as a placeholder in a field that is not used. The following are the fields of a crontab entry:
csh- See C shell.
data set- A grouping of data on a magnetic tape.
default file permissions- When a file is created, a set of default permissions are assigned to it. The default permissions are defined using the umask. command and are typically added to the user's login initialization file to provide a consistent permission mask.
device driver- Software modules that interface with physical resources and understand how to communicate with hardware devices and control their operation. Typically, each device has a unique driver that is provided with the hardware and identified by hardware manufacturer, model, and sometimes hardware version.
directory- A folder used to organize files.
disk label- See volume table of contents.
domain- A group of systems managed as a single entity using a name service such as NIS or NIS+.
Domain Name Service (DNS)- The name service used on the Internet to resolve hostnames to IP addresses and IP addresses to hostnames.
End Of File (EOF) mark- The mark placed on a magnetic tape to signify the end of a file or set of records.
/etc files- The original name service provided with the Unix operating system. Information about other systems is stored in files located under the /etc directory.
file- A group of bytes treated as a unit for storage, retrieval, and manipulation.
file access modes- See standard file permissions.
file server- A networked standalone system used to provide remote access to shared or common data.
file system- A logical collection of files and directories contained in a partition. It can be treated as a single entity when making it available for use (mounting), checking, and repairing.
file system formats- Disk-based file systems are stored on physical disks, CD-ROMs, and diskettes. The- following are the formats of the disk-based file systems:
group account- A unique name and associated group ID used to manage a collection of user accounts.
group ID (GID)- A unique numeric ID assigned to a group account used for group ownership and permissions.
host- A computer system that provides resources to locally and/or remotely logged-on users.
hostname- A name assigned to a host. To provide interoperability on the Internet, the hostname should conform to RFC 952, DOD Internet Host Table Specification.
initialization files- Several initialization files are associated with each user account home directory. These files are used to specify commands to be executed when the associated event occurs. Depending on the login shell being used, there might be a login initialization file, a shell startup file, or a logout file. Commands in the login initialization file are executed when the user logs in. All common shells provide a login initialization file. Commands in the shell startup file are executed whenever the logged-in user starts a shell.
interprocess communication- The cooperative communication between processes.
IP address- A unique 32-bit (4-byte or 4-octet) address assigned to a networked computer using the IP addressing scheme as defined by Internet RFC 1700, Assigned Numbers. The IP address consists of four numbers between 0 and 255 and typically is written in dotted decimal notation, such as 192.168.99.27. The IP addresses are grouped into five network classes on the basis of the value of the first octet.
kernel- A collection of software that manages the physical and logical resources of a computer. These management services include controlling the allocation of memory and other storage devices, controlling the access to peripheral devices (input/output), and controlling the scheduling and execution of processes or tasks. One of the three parts of an operating system (the other parts are the shell and the file system).
kernel modules- Kernel software divided into groups of related functions. Some modules are part of a small, common core of the operating system, some modules provide platform-specific operations, and other modules are device drivers. This architecture allows portions of the kernel to be included or excluded on the basis of the desired functionality or allows portions of the kernel to be updated without replacing the entire kernel. The device drivers are loaded when the device is accessed.
Korn shell- A version of the Unix shell developed by David Korn from AT&T Bell Labs and referred to as ksh. It combines the best features of the Bourne shell and the C shell.
Line Printer (LP) Service- A service that allows users to print files. It provides the ability to add, modify, and delete printer definitions; provides print scheduling; and supports both local and remote printers.
local printer- A printer attached directly to the local system by means of a serial or parallel communication port.
localhost- The loopback IP address for the local system; typically 127.0.0.1, but can be any address starting with 127.
logical device name- A naming convention used to identify disk, tape, and CD-ROM devices and provide either raw access (one character at a time) or block access (via a buffer for accessing large blocks of data). All logical device names reside under the /dev directory, and the /dev/dsk subdirectory identifies the device as a block disk device (the /dev/rdsk subdirectory indicates a raw disk).
login screen- A graphical window used to prompt for and accept a user account name and password.
memory management- Memory management involves keeping track of available memory, allocating it to processes as needed, and reclaiming it as processes release it or terminate.
mount point- A directory in a mounted file system that serves as an access point for another file system. multitasking- The ability to execute more than one process or task at a time. multiuser- The ability of a system to support multiple simultaneous users.
name service- A network service that provides a centralized location for information used by users and systems to communicate with each other across the network. The name service not only stores the information but also provides mechanisms to manage and access that information.
name service switch- A configuration file that is used to select which name services to use and in what order.
namespace- A collection of information regarding systems within the domain of a name service.
network classes- The five classes of networks are based on the first octet of the IP address. These are:
Network File System (NFS)- A network service and type of file system. This service allows local storage, such as file systems, to be accessible by other systems via the network. The version 3 of the NFS protocol is defined by RFC 1813.
NFS client- A system that mounts remote NFS resources made available by NFS servers via the network.
NFS server- A system that shares NFS resources so that they can be accessed
via the network.
partition- A contiguous collection of disk sectors as defined by the partition table. Once a partition is defined in the partition table, a file system can be created within the partition.
physical device name- The name assigned to a device based on the system bus that it is attached to and where on the bus it is attached. The name represents its location on the device tree.
print queue- A list of print requests waiting to be printed. By default, the print requests will be printed in the order they were submitted, unless commands are used to modify print request priorities.
print request- One or more files submitted to a print queue to be printed.
print server- A system that has a local printer attached to it and makes it available to other systems on the network.
process- A task or program currently being executed by the computer system.
RAID- Redundant Array of Inexpensive Disks. The following are the various RAID levels:
remote authentication database- Used to determine which remote hosts and users are considered as being trusted. The rlogin, rsh, and rcp commands use the remote authentication database. This database consists of two types of files: the /etc/host.equiv file, which applies to the entire system, and the .rhosts files, which apply to individual user accounts and are located in the home directories of user accounts.
remote printer- A printer attached to a system (or network interface device) that functions as a print server. Accessing a remote printer from a local system requires defining the local system as a print client to the remote printer.
Request For Comment (RFC)- A document used to publish networking related policies and protocols so that interested parties can submit comments and recommend changes. After a period of time, the RFC is adopted as a standard by the U.S. government and industry. Protocols such as TCP/IP and NFS have been defined by RFCs.
run control (RC) script- A shell script (typically Bourne) written to start and stop various processes and services. An rc script is usually written in two portions: a start portion and a stop portion. The appropriate portion is executed when the system is booted or shut down.
server- A computer system that provides resources to remote clients.
setgid- A special file access mode that sets the effective GID of the user account executing a program to the GID of the program group owner. The setgid permission has an absolute mode of 2000 and a symbolic mode of s.
setuid- A special file access mode that sets the effective UID of the user account executing a program to the UID of the program owner. The setuid permission has an absolute mode of 4000 and a symbolic mode of s.
sh- See Bourne shell.
share- The process of making an NFS resource available for mounting by remote NFS clients.
shell- A software module that provides the interface between users and the kernel. One of the three parts of an operating system (the other parts are the kernel and the file system).
signal- A notification sent to a process to indicate an event or an action that should be performed. Signals are used to terminate processes. The following shows the most frequently used signals to terminate a process:
Slice- See partition.
standard file permissions- Files and directories can have read, write, and execution permissions. Permissions can be assigned to three classes of system accounts: the user account that owns the file, the group account that has group permissions, and everyone else. These are referred to as user, group, and other permissions. The read, write, and execution for user, group, and other can be set independently of one another.
sticky bit- A special file permission that, when set on a directory that allows write permission for everyone, allows only the user account that created the files and subdirectories under that directory to remove those files and subdirectories. This is especially useful for the Amp directory, which is available from any user account. The sticky bit permission has an absolute mode of 1000 and a symbolic mode of t.
subnet mask- A mask used to separate the network portion of an IP address from the host portion. See network classes.
superuser- A special administrative account that provides the ultimate in terms of access to data and services, as it can override any file permissions on the system.
swap space- Disk space used as virtual memory. Swap space can be on a local disk or a remote disk that is accessed via the network.
symbolic file permission mode- An alphabetic notation used to represent the standard file permissions for owner, group, and other. Read access is represented by the letter "r," write by the letter "w," and execution by the letter x.
syslog- A facility used to collect messages from system programs and applications. These are identified by a source facility and priority level. The /etc/syslog.conf file assigns an action with each combination of source and priority level.
syslog actions- The action that should be performed when a syslog message of the identified source.priority is received by the syslogd daemon. The following actions can be defined in the /etc/syslog.conf file:
syslog priority levels- A syslog message can be identified by priority level or severity. This provides a second mechanism (with finer granularity) for han-dling messages on the basis of importance. The following lists the keywords used in the /etc/syslog.conf to identify the severity of messages and control handling. These keywords are ordered on the basis of severity (from most se-vere to least severe):
syslog source facilities- The facilities generating syslog messages can be used to determine where the messages are sent or stored. This allows separate log files for different types of messages based on source. The following are the keywords used in the /etc/syslog.conf to identify the source of messages and control handling:
system run levels- Eight defined levels, each associated with specific functions used to shut down or reboot the system and control system services and resources. The following summarizes the eight run levels:
System V- The version of the Unix operating system developed by AT&T Bell Labs
wheel- A unix system group. Wheel is the group which contains users who can 'su' to root.
user account- A unique name and User ID that control an individual's access to a computer and its resources.
user ID (UID)- A unique numeric ID assigned to a user account that is used for file and process ownership and access permissions.
Some definitions from Solaris System 7 Administrator by Darrel L. Ambro, Coriolis Corp