Ch 1 Flashcards
Mainframes
“big iron” computers for industries to handle large amount of computations
workstation
a computer connected to others through a network
kernel
the main part of OS
the program that is running at all times
system programs
associated with OS but not necessarily part of it
• after being loaded into memory at boot time, it service provided by program becomes SYSTEM PROCESSES or SYSTEM DAEMONS
middleware
included by the OS, is a set of software frameworks that provide additional services usually to mobile operating systems
bootstrap program
program burned into read-only-memory (ROM or typically firmware) that loads the OS from disk to DRAM
interrupt
OS is interrupt driven
• hardware interrupts OS anytime by the way of system bus
• software interrupts are called system calls or monitor calls and will generate a message (trap or exception)
interrupt vector
the array that holds addresses of interrupt services
STORAGE DEFINITIONS AND NOTATION
A kilobyte, or KB, is 1,024 bytes; a megabyte, or MB, is 1,0242 bytes; a gigabyte, or GB, is 1,0243 bytes; a terabyte, or TB, is 1,0244 bytes; and a petabyte, or PB, is 1,0245 bytes.
RAM
random access memory
• any programs to run must be stored here
DMA
direct memory access structure
• reduces # of interruptions by 4000x for data transfer (storage to mem)
• 1 interrupt per data block rather than byte OR interrupts only @ beg. and end of transfer
flash memory
solid-state disk, popular in cameras and personal digital assistants. Flash memory is slower than DRAM but needs no power to retain its contents.
device controller
the device controller is responsible for moving the data between the peripheral devices that it controls and its local buffer storage.
device driver
understands the device controller and provides the rest of the operating system with a uniform interface to the device.
Advantages of multi processor systems
Increased throughput
Increased economy of scale (systems can share can share peripherals, mass storage, and power supplies)
Increased reliability
(CAN BE SYMMETRIC OR ASYMMETRIC)
graceful degradation
service provided is proportional to hardware durability
fault tolerant
systems that go beyond graceful degradation
ensures continued operation
Asymmetric multiprocessing
cores with different specs
• A processor assigns task (boss)
• The rest are assigned tasks
Symmetric multiprocessing
homogeneous cores
each processor performs all tasks within the operating system
Dual Core Design
NUMA - nonuniform memory access (asymmetrical)
• parts of memory may take longer to access than other parts, creating a performance penalty
UMA - uniform memory access (symmetrical)
• access to any RAM from any CPU takes the same amount of time
blade servers
multiple processor boards, I/O boards, and networking boards are placed in the same chassis and they run in the same OS
loosely-coupled
clustered systems
DLM
distributed lock manager
avoids job and data accessing conflicts in cluster systems
SAN
storage-area network - storage shared by a network of computers
