RISC – Reduced Instruction Set Computing
1. Implement the most used instructions in hardware
2. Execute multiple instructions in one cycle
3. Provide synergy between hardware and software
Execution Time = # of Instructions X Clock Cycles/Instruction X Clock Cycle Time
# of Instructions – Depends on Architecture Compiler
Clock Cycles per Instruction – Depends on: Architecture Compiler Implementation
Time taken for a clock cycle – Depends on: Technology Implementation
RS/6000 System Bus Types
2 serial ports
Single-User Graphical Workstation – Requires a Graphics Adapter
Multi-user System – Async Adapter (Ascii Terminals)
Networked System – Server, Network, Clients (PCs)
RS\6000 -Network – PC
X Window Client Programs – Network – X Window Server Software
UP – One Processor
SMP – Multiple Processors that have Shared Memory
Multiple processors accessing the same memory and all disk
SP – Multiple Processors that Shared Nothing
Loosely-coupled processors linked by high-speed interconnect RS/6000SP
System Management Objectives:
1. Minimize time and resources spent managing systesm.
2. Maximize productivity, reliability, and performance.
3. Provide remote system management solutions.
Role of the System Administrator:
Preinstallation planning of:
–Storage allocation/paging space
–Subsystem (printing, networks…)
–Standard naming conventions
–Determine system policies
Install and configure hardware
Configure the software
Configure the network
Create/manage user accounts
Define and manage subsystems
Manage system resources (ei. disk space)
Managing licenses for products
Document system configuration and keept it current
Who Can Perform Administration Tasks?
Usually exclusive to the root user
–Bypasses any file permissions
–Very dangerous to login as root
–Keep root password secure
Some tasks can be performed by other users in special groups such as syste, security, and printq
su command allows you to obtain root’s permissions or permissions of any user whose password you know.
su – switch user
su or “su root” – obtain root permissions but maintain current enviroment
su – or “su – root” – obtain root permissions an root environment
sulog – audit log for root
Note: If more than one person is logging on as root, the system can not keep an audit trail of who performed changes on the system. It is better for each person to log on with their own logon and then use the su command to switch users to root. There is then a log file that keeps an audit trail of who was root when changes are made.
When to use one over the other.
“su” – not to fill up root file system when using system managment tools
“su -” – when your environemt is not as secure as the root environment