Starting with the Pentium model, Intel 80×86 microprocessors introduce extended paging , which allows page frames to be either 4 KB or 4 MB in size.Extended paging is enabled by setting the Page Size flag of a Page Directory entry.The … Continue reading
vmalloc allocates a contiguous memory region in the virtual address space. Although the pages are not con-secutive in physical memory (each page is retrieved with a separate call to alloc_page),the kernel sees them as a contiguous range of addresses. vmalloc … Continue reading
The CPU is connected to memory and various other I/O devices through strips of wires called buses. These buses just take the data, address and control signals from one place to another. There are three types of buses :- #1 … Continue reading
with the help of UM3561 we can create 3 different tone. pin 1 and pin 6 are selecting pins to create different tones
Besides general-purpose hardware caches, Intel 80×86 processors include other caches called translation lookaside buffers or TLB to speed up linear address translation. When a linear address is used for the first time, the corresponding physical address is computed through slow … Continue reading
in smoke sensor we need mq2 sensor and lm324 ic . with the help of variable register we can vary the resistivity of the sensor
In order to manage processes, the kernel must have a clear picture of what each process is doing. It must know, for instance, the process’s priority, whether it is running on the CPU or blocked on some event, what address … Continue reading
#include<stdio.h> #include<malloc.h> int main() { int r,c,i,j,**p; printf(“How many rows,you want to insert: “); scanf(“%d”,&r); printf(“How many columns,you want to insert: “); scanf(“%d”,&c); p=malloc(r*c*sizeof(int)); printf(“Enter your %d*%d matrix elements: “,r,c); for(i=0;i<r;i++) { for(j=0;j<c;j++) scanf(“%d\n”,&(*(*(p+i)+j))); } for(i=0;i<r;i++) { for(j=0;j<c;j++) printf(“%d”,*(*(p+i)+j)); } … Continue reading
For the sake of efficiency, linear addresses are grouped in fixed-length intervals called pages; contiguous linear addresses within a page are mapped into contiguous physical addresses. In this way, the kernel can specify the physical address and the access rights … Continue reading
The paging unit thinks of all RAM as partitioned into fixed-length page frames (they are sometimes referred to as physical pages). Each page frame contains a page, that is, the length of a page frame coincides with that of a … Continue reading
To allow an efficient search through processes of a given type (for instance, all processes in a runnable state) the kernel creates several lists of processes. Each list consists of pointers to process descriptors. A list pointer (that is, the … Continue reading
A logical address consists of two parts: a segment identifier and an offset that specifies the relative address within the segment. The segment identifier is a 16-bit field called Segment Selector, while the offset is a 32-bit field. To make … Continue reading
Flash devices, including NOR flash devices such as CFI flash chips and NAND flash devices such as the DOC, are not like disk storage devices. They cannot be written to and read from arbitrarily. To understand how to operate flash … Continue reading
CRAMFS was written by Linus Torvalds as a filesystem with a bare minimum feature set. It is a very simple, and sometimes simplistic, compressed and read-only filesystem aimed at embedded systems CRAMFS has the following limitations: The maximum size a … Continue reading
$make Error : In file included from contrib/elftrunc.c:5: /home/Amit/control-project/daq-module/build-tools/dietlibc-0.21/include/stdio.h:18: warning: ‘malloc’ attribute ignored contrib/elftrunc.c: In function ‘main’: contrib/elftrunc.c:141: warning: implicit declaration of function ‘memcmp’ contrib/elftrunc.c:145: warning: implicit declaration of function ‘strncpy’ contrib/elftrunc.c:145: warning: incompatible implicit declaration of built-in function ‘strncpy’