HOME

Top 10 List of Week 03

1. File Concept
   A file is a collection of correlated information which is recorded on secondary or non-volatile storage like magnetic disks, optical disks, and tapes. It is a method of data collection that is used as a medium for giving input and receiving output from that program.

2. File Attributes
   A file can have a bunch attributes many of which are name, type, identifier, size, location, date modified, etc.

3. File Operations
   The operating system can supply system calls to operate on a file. The operations include create, write, read, reposition, delet and truncate files.

4. File Types
   File type is considered an extention of a file and to design an operating system means we have to decide which types of file are supported within the operating system.

5. Types of Access
   The need to protect files is a direct result of the ability to access files. Systems that do not permit access to the files of other users do not need protection. Thus, we could provide complete protection by prohibiting access.

6. Partitions and Mounting
   Physical disks are commonly divided into smaller units called partitions. They can also be combined into larger units, but that is most commonly done for RAID installations and is left for later chapters. Partitions can either be used as raw devices ( with no structure imposed upon them ), or they can be formatted to hold a filesystem ( i.e. populated with FCBs and initial directory structures as appropriate. ) Raw partitions are generally used for swap space, and may also be used for certain programs such as databases that choose to manage their own disk storage system. Partitions containing filesystems can generally only be accessed using the file system structure by ordinary users, but can often be accessed as a raw device also by root.

7. File Sharing
   File sharing is the public or private sharing of computer data or space in a network with various levels of access privilege.

8. Remote File Systems
   Remote file systems are implemented by a collection of software components. The number and complexity of the software components required varies based on the design and complexity of the remote file system.

9. Access Control
   Access control for an operating system determines how the operating system implements accesses to system resources by satisfying the security objectives of integrity, availability, and secrecy. Such a mechanism authorizes subjects (e.g., processes and users) to perform certain operations (e.g., read, write) on objects and resources of the OS (e.g., files, sockets).

10. Allocation Methods
    The allocation methods define how the files are stored in the disk blocks. There are three main disk space or file allocation methods. Contiguous Allocation, Linked Allocation and Indexed Allocation.