On 25th May , session of i.t club was held...The discussion was held on the following topics---
@ Windows Registry@ Kernel
1..Windows Registry..
The Windows Registry is
a hierarchical database that stores configuration settings and
options on Microsoft Windows operating systems. It contains settings
for low-level operating system components and for applications running on the
platform that have opted to use the registry. The kernel, device
drivers, services, SAM, user interface and third party
applications can all make use of the registry. The registry also provides a
means to access counters for profiling system performance.
When first
introduced with Windows 3.1, the Windows registry's primary purpose was to
store configuration information for COM-based components. With the
introduction of Windows 95 and Windows NT, its use was extended to tidy up the
profusion of per-program INI files that had previously been used to
store configuration settings for Windows programs..] It is
not a requirement for a Windows application to use the Windows Registry—for
example, the .NET Framework applications use XML files for
configuration, whileportable applications usually keep their configuration
data within files in the directory/folder where the
application executable resides.
Backups and recovery
Different editions
of Windows have supported a number of different methods to back up and restore
the registry over the years, some of which are now deprecated:
·
System Restore can back up the registry and restore it as long as
Windows is bootable, or from the Windows Recovery
Environment starting with Windows Vista.
·
NTBackup can back up the registry as part of the System
State and restore it. Automated System Recovery in Windows
XP can also restore the registry.
·
On Windows NT-based systems, the Last Known Good Configuration option
in startup menu relinks the HKLM\SYSTEM\CurrentControlSet key, which
stores hardware and device driver information.· Windows 98 and Windows Me include command line (Scanreg.exe) and GUI (Scanregw.exe) registry checker tools to check and fix the integrity of the registry, create up to five automatic regular backups by default and restore them manually or whenever corruption is detected. The registry checker tool backs up the registry, by default, to%Windir%\Sysbckup Scanreg.exe can also run from MS-DOS.
2..Kernel..
The kernel's primary function is to manage the computer's hardware and resources and allow other programs to run and use these resources. Typically, the resources consist of:
- The Central Processing Unit. This is the most central part of a computer system, responsible for running or executing programs. The kernel takes responsibility for deciding at any time which of the many running programs should be allocated to the processor or processors (each of which can usually run only one program at a time)
- The computer's memory. Memory is used to store both program instructions and data. Typically, both need to be present in memory in order for a program to execute. Often multiple programs will want access to memory, frequently demanding more memory than the computer has available. The kernel is responsible for deciding which memory each process can use, and determining what to do when not enough is available.
- Any Input/Output (I/O) devices present in the computer, such as keyboard, mouse, disk drives, USB devices, printers, displays, network adapters, etc. The kernel allocates requests from applications to perform I/O to an appropriate device (or subsection of a device, in the case of files on a disk or windows on a display) and provides convenient methods for using the device (typically abstracted to the point where the application does not need to know implementation details of the device).
Key aspects necessary in resource management are the definition of an execution domain (address space) and the protection mechanism used to mediate the accesses to the resources within a domain.
Kernels also usually provide methods for synchronization and communication between processes called inter-process communication (IPC).
A kernel may implement these features itself, or rely on some of the processes it runs to provide the facilities to other processes, although in this case it must provide some means of IPC to allow processes to access the facilities provided by each other.
Finally, a kernel must provide running programs with a method to make requests to access these facilities.