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Styresystemer og tjenester

Styresystemer og tjenester. Indhold: Introduktion til styresystemer. Processer og tråde. Synkroniseringsmetoder og InterProcesCommunikation. Memory management. I/O og devicedrivere. Filsystemer. Distribuerede systemer. Sikkerhed. Systemovervågning og konfigurering.

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Styresystemer og tjenester

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  1. Styresystemer og tjenester Indhold: • Introduktion til styresystemer. • Processer og tråde. • Synkroniseringsmetoder ogInterProcesCommunikation. • Memorymanagement. • I/O og devicedrivere. • Filsystemer. • Distribuerede systemer. • Sikkerhed. • Systemovervågning og konfigurering. • Operativsystemudvikling samt USB. Styresystemer og tjenester

  2. Operativsystem design. Algorithme kode Event-driven kode Styresystemer og tjenester

  3. Hiding the Hardware (1) CPU-dependent conditional compilation Styresystemer og tjenester

  4. Hiding the Hardware (2) Word-length dependent conditional compilation Styresystemer og tjenester

  5. Space-Time Trade-offs (1) A procedure for counting bits in a byte (a) A procedure to count the 1 bits in a byte Styresystemer og tjenester

  6. Space-Time Trade-offs (2) • A macro to count the bits • A macro to access bit count in a table (b) Macro to count the bytes (c) Macro to look up the count Styresystemer og tjenester

  7. Space-Time Trade-offs (3) (a) Part of an uncompressed image with 24 bits per pixel (b) Same part compressed with GIF, 8 bits per pixel (c) The color palate Styresystemer og tjenester

  8. Aplikationsprogram Trap OPS struktur. Kald af OPS.-funktion. Fx fopen() APP User mode System kald Memory management Device driver kernel OPS Protokolstak Filsystem Supervisor mode CPU HW USB Memory DISK Ethernet Styresystemer og tjenester

  9. Operativsystem design. Lag Styresystemer og tjenester

  10. OPS struktur. Exokerne APP Ext. Memory management Device driver Protokolstak Ext. kernel Filsystem User mode Supervisor mode OPS Minimal kerne, mem.management og IPC HW CPU Memory Ethernet DISK USB Styresystemer og tjenester

  11. Operativsystem design. System call handler Lag Styresystemer og tjenester

  12. OPS struktur. Micro kerne eller Client server system APP Ext. Memory management Protokolstak Device driver Ext. kernel Filsystem User mode Supervisor mode OPS Minimal kerne, mem.management og IPC HW CPU Memory Ethernet DISK USB Styresystemer og tjenester

  13. USB – Universal Seriel Bus • USB Speeds • High Speed - 480Mbits/s • Full Speed - 12Mbits/s • Low Speed - 1.5Mbits/s Et host kontrolleret system (Master/slave). Kun en Master nemlig PC’en Max 127 devices/slaver pr bus. Styresystemer og tjenester

  14. Hardware 1: VBUS (5 volts) Max 500 mA 2: D- 3: D+ 4: Ground Styresystemer og tjenester

  15. USB protokollen • Hver USB transaction består af: • Token Packet, • Optional Data Packet, • Status Packet Styresystemer og tjenester

  16. Token Packet • Der er tre typer af token Packet, • In - Host ønsker af læse fra device. • Out - Host ønsker at sende data til device. • Setup – Starte kontrol sekvens. • Token Packets format: Sync PID ADDR ENDP CRC5 EOP Styresystemer og tjenester

  17. Data packets Sync PID Data CRC16 EOP • Max payload size for low-speed devices: 8 bytes. • Max payload size for full-speed devices: 1023 bytes. • Maxpayload size for high-speed devices: 1024 bytes. Styresystemer og tjenester

  18. Handshake Pavket • Der er tre typer af Handshake Packets • ACK – Acknowledgment.En pakke er modtaget korrekt. • NAK – Meddeler at: • - en divice ikke kan sende eller modtage data. • - interrupt en transactions for at informere hosten om der ingen • data er at sende. • STALL – Devicen er i en tilstand der kræver behandling. • Handshake Packets har følgende format: Sync PID EOP Styresystemer og tjenester

  19. Start of Frame Packet SOF packet bestående af et 11-bit frame nummer sendes af hosten hver 1ms ± 500ns (full speed)eller hver 125 µs ± 0.0625 µs (high speed). Sync PID Frame Number CRC5 EOP Styresystemer og tjenester

  20. Transfers: Setup Styresystemer og tjenester

  21. Transfers: Data Styresystemer og tjenester

  22. Opretningssekvens. • The host or hub detects the connection of a new device via the device's • pull up resistors on the data pair. The host waits for at least 100ms allowing • for the plug to be inserted fully and for power to stabilise on the device. • Host issues a reset placing the device is the default state. The device may • now respond to the default address zero. • The MS Windows host asks for the first 64 bit of the Device Descriptor. • After receiving the first 8 bytes of the Device Descriptor, it immediately issues • another bus reset. • The host now issues a Set Address command, placing the device in the • addressed state. • The host asks for the entire 18 bytes of the Device Descriptor. • It then asks for 9 bytes of the Configuration Descriptor to determine the • overall size. • The host asks for 255 bytes of the Configuration Descriptor. • Host asks for any String Descriptors if they were specified. Styresystemer og tjenester

  23. Software http://jusb.sourceforge.net/ http://www.steelbrothers.ch/jusb/ http://www.linux-usb.org/ Styresystemer og tjenester

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