Matakuliah
Tahun
Versi/Revisi
: T0316/sistem Operasi
: 2005
:5
Pertemuan 26
Proses dan Threads pada
Sistem Operasi Windows
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• membandingkan sistem operasi Linux dan
Windows 2000 (C4)
2
Outline Materi
•
•
•
•
•
•
•
•
•
Proses dan threads pada windows 2000
Komunikasi inter proses
Penjadwalan
Proses booting pada windows 2000
Pengaturan memory
Pengaturan I/O
Device driver
Sistem file pada windows 2000
Securiti pada windows 2000
3
Processes and Threads (1)
Basic concepts used for CPU and resource management
4
Job
• Sekumpulan proses
• Share quota dan resource limit
– Jumlah proses
– CPU time
– dll
5
Process
• Container for resources
– Created via Win32 call
• CreateProcess (Win32 API function di dalam
library kernel32.dll)
• NTCreateprocess (system call)
– Minimal satu thread
– Serangkaian handles
– Access token  for security information
– 4 GB adress space
6
Thread
• Entity scheduled by kernel
• Created via Win32 call
– Created using CreateThread (Win32 API function di
dalam library kernel32.dll)
– NTCreateThread (system call)
• State: ready, running, block
• Normal vs daemod threads (in user and kernel
space, respectively)
• Thread switching
– (between user and kernel mode)
• Dapat memiliki beberapa fibers
7
Fiber
•
•
•
•
•
Lightweight thread
Lightweight pseudo-parallelism
Scheduled in user space  faster
Tidak termasuk executive object
Melalui Win32 API tanpa system call
8
Komunikasi antar process
• Threads komunikasi lewat
– Pipes
– Named pipes (dengan network)
– Mailslot
• only on Windows 2000
• One-way, un-guaranteed delivery, allow broadcast
– Socket  connect processes on different machine
• Similar to pipe
– Remote procedure calls
– Shared files
9
Komunikasi (2)
• Synchronization mechanism
– Semaphore
– Mutexes
– Critical sections
– Events
• Set or cleared
• Eg. Set  waiting threads are released
10
Penjadwalan
• Scheduler diaktifkan ketika
– Threads terhalang (blocked) misal oleh
semaphore
– Thread memberi signal (misal up on
semaphore) pada suatu object
– Quantum habis
– Operasi IO selesai
– Batas waktu menunggu habis
11
Emulasi MS-DOS
• Run as many MSDOS programs as
prossible
• NT vitual DOS machine  ntvdm
– Monitor MSDOS program and carry out its
system calls
• Trampoline
– Emulation to bounce back MSDOS IO request
12
MS-DOS Emulation
How old MS-DOS programs are run under Windows 2000
13
Booting Windows 2000
• Processes starting up during boot phase
• Those above the line are always started
• Those below are examples of services which could be
started
14
Process Booting
• Baca master boot record  sektor pertama dari
disk pertama
• Assembly language program
• Baca partition table
• Cari boot sector  sektor pertama dalam partisi
yang berisi bootable OS
• Baca root directory
• Cari dan execute file ntldr (nt loader)
• Baca file boot.ini
• Baca files hal.dll, ntoskrnl.exe, bootvid.dll (video
driver)
15
Process Booting (2)
• First user process  session manager
(smss.exe)
• Aktifkan win32 environment subsytem
(crss.exe)
• Baca registry  hives
• Login daemon  winlogon.exe
• Authentication manager  lsass.exe
• Services.exe  parent process of all
services
16
Pengaturan Memory
• Memory Virtual
– Proses  32 bit virtual address (4GB virtual
address space)
– Upper 2GB  untuk OS, shareable
– 4KB page size (Pentium), atau 8/16KB
(Itanium)
– Demand paged
– States dari virtual page
• Free, reserved, committed
17
Pengaturan Memory (2)
• Memory manager
– Berkaitan dengan proses, bukan thread
(scheduler)
– Virtual Address Descriptor (VAD)
• Contains list of range of address mapped, backing
store file and offset, protection code
• Balance Set Manager
– Kernel daemon thread
– Kontrol ketersediaan free pages
18
Pengaturan Memory (3)
• Working set manager
– Thread yang mengatur working set bagi
proses
– Berdasarkan parameter min dan max size of
working set
– Local allocation strategy
• Win32 API
– To allocate, free, protect and query Virtual
Address Space (VAS)
– Pengaturan memory-mapped files
19
Pengaturan Physical Memory
• Page lists
– Standby page list
– Modified (dirty) page list
– Free list
– Zeroed page list
• Page frame databases
– Banyaknya entries  banyaknya pages
dalam RAM
– Index menurut physical page frame #
20
Pengaturan Input/Output
• Plug and Play Manager
– Enumerable bus  allows request to the slot for self
identification of devices
– Mengalokasikan H/W resource (eg interrupt level)
– Memilih driver yang sesuai
– Load ke memory & create driver object
• Win32 API
– Utama pada window management
– Management of text  colour, size, width, typeface
– clipboard
21
Pengaturan IO (2)
• Device Drivers
– Windows driver model
•
•
•
•
•
•
•
IO request dengan format standar
Object based
Support plug-and-play
Support power management
Configurable
Reentrant
Portable
– Stacked drivers  request must pass a sequence of
drivers
– Filter drivers  perform transformation on the data
22
File System
• Support FAT-16, FAT-32, dan NTFS
• NTFS
– 64 bit disk address
– Long file name (255 chars)
– Volume (partition) terdiri dari
• Files, directories, bitmaps, and data structures
– Block (cluster) size  512 bytes hingga 64
KB  compromised 4 KB
– Master File Table (MFT)
• Each describe one file/directoriy
23
File System (2)
• Win32 API
– File  create, delete, open, close, read, write, etc
– Mutual exclusion  lock file, unlock file
– Directory  create, remove, find first file, etc
• NTFS File name Lookup
– Dimulai dari root object manager name space
– Directory \??
• Contains the disk letter (eg. A, C, D …)
• ??  read first in ASCII
– Support hard link
– Support symbolic links (reparse point)
24
File System (3)
• NTFS File Compression
– Transparent file compression
– Compressed mode  compress blocks as written and
uncompress as read
– Run compression algorithm
• NTFS File Encryption
– Option to encrypt files
– Done by EFS (Encrypting File Standard) driver
• A variant of DES (Data Encryption Standard)
– Generates a random 128 bit file key
25
File System Structure (1)
The NTFS master file table
26
File System Structure (2)
The attributes used in MFT records
27
File System Structure (3)
An MFT record for a three-run, nine-block file
28
File Name Lookup
Steps in looking up the file C:\maria\web.htm
29
File Compression
(a) An example of a 48-block file being compressed to 32
blocks
30
(b) The MFT record for the file after compression
Security
• Mewarisi security dari Win NT
• Identifikasi user dan group dengan Security ID (SID)
• Access token  for each process
– DACL (Discretionary Access Control List)
• contains who may use the object
– ACE (Access Control Elements)
• Access or deny
– Security Descriptor
• Header + DACL + one or more ACEs
• Win32 API
– Berbasis security descriptor
– Menggunakan security dan SAM (Security Account Manager)
keys di dalam registry
31
Caching
• Cache manager
• Untuk keperluan kinerja sistem
• Menyimpan blok-blok file yang baru
digunakan untuk kegunaan berikutnya
• Berdasarkan virtual block (bukan physical
block)
• Diacu (referenced) dengan (file, offset)
• Sebesar 256 KB VAS dipetakan (mapped)
ke file
32
Caching in Windows 2000
The path through the cache to the hardware
33