Virtual memory
... access. – Fetch page table entry. – Fetch data. • Virtual memory scheme would have the effect of doubling the memory access time. • To overcome this problem, most virtual memory schemes make use of a special cache for page table entries, usually called a translation lookaside buffer (TLB). • This ca ...
... access. – Fetch page table entry. – Fetch data. • Virtual memory scheme would have the effect of doubling the memory access time. • To overcome this problem, most virtual memory schemes make use of a special cache for page table entries, usually called a translation lookaside buffer (TLB). • This ca ...
CS/ECE 252: INTRODUCTION TO COMPUTER
... You know a byte is 8 bits. A 4-bit quantity is called a nibble. If a byte-addressable memory has a 16-bit address, how many nibbles of storage are in this memory? ...
... You know a byte is 8 bits. A 4-bit quantity is called a nibble. If a byte-addressable memory has a 16-bit address, how many nibbles of storage are in this memory? ...
SC PE
... (hardware), which is set to a fixed time-slice. • When an interrupt is triggered, CPU hardware 1. Stops the execution of the current program, 2. Saves the context of the current program, 3. Jumps to the subroutine that handles the ...
... (hardware), which is set to a fixed time-slice. • When an interrupt is triggered, CPU hardware 1. Stops the execution of the current program, 2. Saves the context of the current program, 3. Jumps to the subroutine that handles the ...
OS support
... time-sharing long-term scheduler (queue of all jobs potentially schedulable) short-term scheduler (queue of processes that are ready to execute) medium-term scheduling (queue of jobs that can reside in memory) blocked monitoring (queue of processes blocked for resources) ...
... time-sharing long-term scheduler (queue of all jobs potentially schedulable) short-term scheduler (queue of processes that are ready to execute) medium-term scheduling (queue of jobs that can reside in memory) blocked monitoring (queue of processes blocked for resources) ...
PowerPoint XP
... for development, evolution, performance, and security? How do we design a distributed OS that can be used on multiple machines? How do we use multi-processor machines effectively? ...
... for development, evolution, performance, and security? How do we design a distributed OS that can be used on multiple machines? How do we use multi-processor machines effectively? ...
Virtual Memory - classes.cs.uchicago.edu
... PFN for the corresponding /VPN # to support translation Control bits to support replacement Dirty bit indicate if we need to “write back” Protection bits to enable access control and protection ...
... PFN for the corresponding /VPN # to support translation Control bits to support replacement Dirty bit indicate if we need to “write back” Protection bits to enable access control and protection ...
08 Operating System Support
... Segmentation is used to define logical memory partitions subject to access control, and paging is used to manage the allocation of memory within the partitions ...
... Segmentation is used to define logical memory partitions subject to access control, and paging is used to manage the allocation of memory within the partitions ...
CH08-COA9e
... Segmentation is used to define logical memory partitions subject to access control, and paging is used to manage the allocation of memory within the partitions ...
... Segmentation is used to define logical memory partitions subject to access control, and paging is used to manage the allocation of memory within the partitions ...
Disco
... • Disco intercepts all device accesses from the virtual machine and forwards them to the physical devices • Each Disco device defines a monitor call used by the device driver to pass all command arguments in a single trap • DMA requests to translate the physical addresses into machine addresses. ...
... • Disco intercepts all device accesses from the virtual machine and forwards them to the physical devices • Each Disco device defines a monitor call used by the device driver to pass all command arguments in a single trap • DMA requests to translate the physical addresses into machine addresses. ...
lec15
... In reality, pages are scattered throughout physical memory The mapping is invisible to the program Protection is provided because a program cannot reference memory outside of its VAS ...
... In reality, pages are scattered throughout physical memory The mapping is invisible to the program Protection is provided because a program cannot reference memory outside of its VAS ...
Lecture17
... Slab one or more physically contiguous pages Cache of one or more slabs. Single cache for each unique kernel data ...
... Slab one or more physically contiguous pages Cache of one or more slabs. Single cache for each unique kernel data ...
OSTEP 13 Address Space
... Only the OS, through its tricky techniques of virtualizing memory, that knows where in the physical memory of the machine these instructions and data values lie If you print out an address in a program, it’s a virtual one, an illusion of how things are laid out in memory; only the OS (and the hardwa ...
... Only the OS, through its tricky techniques of virtualizing memory, that knows where in the physical memory of the machine these instructions and data values lie If you print out an address in a program, it’s a virtual one, an illusion of how things are laid out in memory; only the OS (and the hardwa ...
08_Operating System Support
... • Simplifies handling of growing data structures • Allows programs to be altered and recompiled independently, without relinking and re-loading • Lends itself to sharing among processes • Lends itself to protection • Some systems combine segmentation with paging ...
... • Simplifies handling of growing data structures • Allows programs to be altered and recompiled independently, without relinking and re-loading • Lends itself to sharing among processes • Lends itself to protection • Some systems combine segmentation with paging ...
Chapter 10 – Operating Systems Roles of an Operating System
... There is only one CPU and therefore only one set of CPU registers, which contain the values for the currently executing process - each time a process is moved to the running state: – Register values for the currently running process are stored into its PCB – Its PCB is moved to the list of the state ...
... There is only one CPU and therefore only one set of CPU registers, which contain the values for the currently executing process - each time a process is moved to the running state: – Register values for the currently running process are stored into its PCB – Its PCB is moved to the list of the state ...
Disco
... execution of real CPU's • Same execution speed as running on real CPU's • Each virtual CPU has a data structure like a process table entry in traditional O.S. o Contains state of virtual CPU • Runs in kernel mode with full access • Simple scheduler allows virtual processors to be shared ...
... execution of real CPU's • Same execution speed as running on real CPU's • Each virtual CPU has a data structure like a process table entry in traditional O.S. o Contains state of virtual CPU • Runs in kernel mode with full access • Simple scheduler allows virtual processors to be shared ...
CSE451 Introduction to Operating Systems
... address space to be resident in physical memory • program can also execute on machines with less RAM than it “needs” – many programs don’t need all of their code or data at once (or ever) • e.g., branches they never take, or data they never read/write • no need to allocate memory for it, OS should a ...
... address space to be resident in physical memory • program can also execute on machines with less RAM than it “needs” – many programs don’t need all of their code or data at once (or ever) • e.g., branches they never take, or data they never read/write • no need to allocate memory for it, OS should a ...
Disco : Running commodity operating system on scalable
... by monitor, if request size is multiple of machine page size, then monitor has to remap the machine pages into VM physical memory. •Pages are read only and an attempt to modify will generate copy on write fault handled by monitor. Read only pages are are brought in from disk can be transparently sha ...
... by monitor, if request size is multiple of machine page size, then monitor has to remap the machine pages into VM physical memory. •Pages are read only and an attempt to modify will generate copy on write fault handled by monitor. Read only pages are are brought in from disk can be transparently sha ...
ppt
... by monitor, if request size is multiple of machine page size, then monitor has to remap the machine pages into VM physical memory. •Pages are read only and an attempt to modify will generate copy on write fault handled by monitor. Read only pages are are brought in from disk can be transparently sha ...
... by monitor, if request size is multiple of machine page size, then monitor has to remap the machine pages into VM physical memory. •Pages are read only and an attempt to modify will generate copy on write fault handled by monitor. Read only pages are are brought in from disk can be transparently sha ...
Chap 6: Virtual Memory
... • Large page tables are cumbersome and slow, but with its uniform memory mapping, page operations are fast. Segmentation allows fast access to the segment table, but segment loading is laborintensive. • Paging and segmentation can be combined to take advantage of the best features of both by assigni ...
... • Large page tables are cumbersome and slow, but with its uniform memory mapping, page operations are fast. Segmentation allows fast access to the segment table, but segment loading is laborintensive. • Paging and segmentation can be combined to take advantage of the best features of both by assigni ...
Main Memory
... table which contains base address of each page in physical memory – Page offset (d) – combined with base address to define the physical memory address that is sent to the memory unit page number ...
... table which contains base address of each page in physical memory – Page offset (d) – combined with base address to define the physical memory address that is sent to the memory unit page number ...
Lecture 15 - NCSU COE People
... • Sharing of code. Two users are running the same code “simultaneously.” How are they to be kept from overwriting each other’s data? The first of these problems can be solved by partitioning main memory into several regions. Architecture II: Partitions within main memory. Each program runs within a ...
... • Sharing of code. Two users are running the same code “simultaneously.” How are they to be kept from overwriting each other’s data? The first of these problems can be solved by partitioning main memory into several regions. Architecture II: Partitions within main memory. Each program runs within a ...
ppt - Computer Science
... Virtual machine is assigned resources by Disco which manages a pool of processing elements/memory resources Decouple Operating System from machine hardware. OS runs on virtual machine ...
... Virtual machine is assigned resources by Disco which manages a pool of processing elements/memory resources Decouple Operating System from machine hardware. OS runs on virtual machine ...
08 Operating System Support
... • Protection bits give 4 levels of privilege —0 most protected, 3 least —Use of levels software dependent —Usually level 3 for applications, level 1 for O/S and level 0 for kernel (level 2 not used) —Level 2 may be used for apps that have internal security e.g. database —Some instructions only work ...
... • Protection bits give 4 levels of privilege —0 most protected, 3 least —Use of levels software dependent —Usually level 3 for applications, level 1 for O/S and level 0 for kernel (level 2 not used) —Level 2 may be used for apps that have internal security e.g. database —Some instructions only work ...
Operating system
... Pentium II Segmentation • Each virtual address is 16-bit segment and 32-bit offset • 2 bits of segment are protection ...
... Pentium II Segmentation • Each virtual address is 16-bit segment and 32-bit offset • 2 bits of segment are protection ...
Memory management unit
A memory management unit (MMU), sometimes called paged memory management unit (PMMU), is a computer hardware unit having all memory references passed through itself, primarily performing the translation of virtual memory addresses to physical addresses. It is usually implemented as part of the central processing unit (CPU), but it also can be in the form of a separate integrated circuit.An MMU effectively performs virtual memory management, handling at the same time memory protection, cache control, bus arbitration and, in simpler computer architectures (especially 8-bit systems), bank switching.