Chapter 8
MULTITASKING:
-The ability of an OS to support numerous processes at the same time
omaintaining memory pointers
ooffering access to I/O data
oproviding cycles of the CPU for computations
-Can support as many simultaneous processes as CPUs
TIMESLICING:
-Simulated multitasking
-Occurs when the CPUs computing cycle are divided between more than one task
PREEMPTIVE MULTITASKING:
-OS controls what process gets access to the CPU and for how long
COOPERATIVE MULTITASKING:
-OS does not have the ability to stop a process
-No other process can access the CPU until the current process releases it
CHARACTERISTICS OF NETBIOS NAMES:
-No longer than 15 characters (16th character included but the OS manages it outside of user control)
-Certain characters many not appear
-Ending with a $ prevents the name from appearing on a browser list
DIRECTORY SERVICES:
-Works for a network much like the white/yellow pages
-Lookup by name, types of services or resources
-Windows 2000 1st directory NOS (Active Directory)
-Netware Novell Directory Services
REDIRECTOR:
-A software component operating at the Presentation layer of the OSI model and found on both client and server network operating systems
-It examines a request (printer or data file..example) and determines if the resource is local or remote
olocal the redirector sends the request to the CPU for immediate processing
oremote sends the request over the network to the server or host of that particular source
-Novell requestor
-Linux shell
-Most commonly occurs when the local printer is mapped to a networked drive
Purpose of NOS:
-Controls the operations of a computer, including local hardware activity as well as communication over network media
-Enables sharing resources
-Managing peripherals
-Maintaining security
-Supporting privacy
-Controlling user access
-Windows 2000 and Netware (v 4 and higher) include built-in directory services that permit users simply to request resources and services and the work of locating and providing access to resources and services on the users behalf
-There are two fundamental networked services:
oSharing printers
oSharing directories
CHAPTER 9
CLIENT-BASED MULTIVENDOR SOLUTION:
-When multiple redirectors are loaded on a client, the client can communicate with servers from different vendors
-Ex. If Windows 98 client requires access to a Windows 2000 Server and a Novell Netware Server, you can load a redirector for each operating system onto that client
-Relies on client computers redirectors to decide to which server to send the request
SERVER-BASED MULTIVENDOR SOLUTION:
-A server that can readily communicate with clients from multiple vendors, such as Windows 2000 Server
SAMBA:
-An open source software suite that makes Linux servers look and act like Windows servers
-It permits DOS or Windows clients to access Linux or Unix-based file systems and services w/o special software on the client end
-A server-based solution; software and services need be installed only on a small number of servers
-Can be downloaded and installed for free
NFS:
-Network File System a distributed file system originally developed at Sun Microsystems
-Supports network-based file and printer sharing using TCP/IP-based network protocols
-Native to Unix
-Allows networked machines to export portions of their local file systems and make them available to authorized users on the network
TERMINAL SERVICES:
-A software subsystem for NT and 2000 server that permits clients to run large or complex applications on computers with minimal processing power by transferring the burden of client processing to the server
-Providing access:
to modern Windows applications on older PCs or thin clients that might not otherwise be able to run those applications
to centralized applications or services that would otherwise have to be installed on client machines
-permitting remote clients using narrow bandwidth connections to access modern, powerful Windows applications w/o bandwidth-related performance delays
CENTRALIZED COMPUTING:
-A computing environment in which all processing takes place on a mainframe or central computer
-Dumb terminals connect directly to the mainframe
-Thin Clients attached to a terminal server or some kind can also access a mainframe
-creates a large volume of data and does not efficiently use the PCs
FRONT END VS BACK END:
-front end a client
opresents data in a usable form
oaccepts instructions from the user, formats them for the server and send its requests to the server
-back end a server
odoes not contain user interface software
ostores and maintains data; most database functions occur within it
oreceives requests from clients, processes them, and returns information to the client
BENEFITS OF CLIENT/SERVER ENVIRONMENT:
-methods of implementation:
osingle database server
omultiple database servers
distributed
multi-tiered database
-simplifies network administration
-centralized user accounts
-secure
-centralized file storage
-simplifies back-up
CHAPTER 10
USER MANAGER FOR DOMAINS:
-make sure all users can access resources they are allowed to access but cant access resources they dont have permission to access
-user account
ocollection of information about a user
account name
associated password
a set of access permissions for network resources
-group account
oumbrella account to which individual accounts may be assigned to grant them a predetermined set of rights
-two predefined accounts in NT /2000
oadministrative
oguest
-network admin decisions relate to:
opasswords
ologon hours
oauditing
-global groups
oa group meant to be used in more than one domain
ocan include local users
-local groups
oa group meant to be used in a single node
ocan include individual users and global users
-global groups can include individual users
-local groups can include individual users and global groups
-native mode
ono NT servers may act as a domain controllers in that domain
-Mixed mode
oWhen NT servers do function as domain controllers with 2000 Directory Service
-Windows NT/2000 server default groups:
oDomain admins
oDomain users
oDomain guests
-Automatic groups
oEveryone
oAuthenticated users
oInteractive
oNetwork

-Trust relationships
oOne domain permits members of another domain to access its resources
oUsed to manage cross-domain communications
oWindows NT
1-way or 2-way trust between domains, so that members of a given domain can access resources in another domain
owindows 2000
automatic trust relationships are all two way
DISK MIRRORING VS DUPLEXING
-Disk mirroringdata is written to two hard drives, rather than one, so that if one disks fails, then the data remains accessible
-Disk duplexing data is written to two hard drives, each with its own disk controller, so that if one disk or controller fails, then the data remains accessible