File system Concept A file is collection of related information recorded on secondary storage by sequence of bits, bytes, lines or records. All data written to secondary storage in file format, which can be numeric, alphabetic, alphanumeric or binary. Attributes of files: - name to which system refers when file participates in process; - file identifier; - file type ( text, source, object, executable); - location; - size; - protection level; - creation / modification date. Operations with files: - creating: defining file place in the system and creating directory entry; - writing: specifying file name and information which file will contain; - reading; - repositioning within file; - deleting: releasing both file space and directory entry; - truncating: erasing file content. File access - sequential access: file record is read one after another; - direct access: file allows random access to any block; - indexed access: search is done through file index. Directories As files can be different in sizes and types, they need tp be organised. Then each storage volume contains information about files in this storage-volume table of contents. By complexity of structure following directories types defined: - Single level: all file are on the same level and all files have unique names; - Two level: each user has own file directory …show more content…
Users are allowed to view all file under single directory, not even knowing under which particular file system it is stored. Location of each file, directory or link is described by object called inode. Inode is unique to particular file system and does not include name, which is allows creating multiple hard links that map several file names to the same inode. Each file is represented by file descriptor. VFS uses Dentry (Directory Entry) to map file using inode and file names. For each file name there is pointer to corresponding inode. Thus, the system resolves pathname-inode conversion
Icefish are among the few fish families that thrive in the oxygen-rich cold waters surrounding Antarctica. They have evolved a set of unique adaptations that enable them to survive in an environment that would be deadly to other fish. Several of these adaptations are associated with major health problems in humans. Can icefish help
Every piece of information must be traceable back to the data input that produced it. The main action of audit trail is captures a sources of all data items at the time of getting entrance into the system. The other constituent of input control and security involves data security rules and measures to protect data from being or lost or damaged. The records retention policy is the practice of storing documents in a safe location and making sure to see to legal requirements or business needs. Input security and control also involves the process of encrypting or encryption of data so only users with the code it software can read
data inside documents as well as to files and folders, and can also call up
Files location and operation are hidden to clients. Clients don’t need to know how the system is designed, how data is located and accessed, and how faults are detected. The logic name of the file should not be changed even when relocate the file. Client sends requests to handle files without thinking about the complex mechanisms of the underlying system which performs operations. The DFS server just provide an access to the system with some simple tools. DFSs also use local caching for frequently used files to eliminate network traffic and CPU consumption caused by repeated queries on the same file and represent a better performance. And the local caching also give a fast access to those frequently used files. So caching has a performance transparency by hiding data distribution to users. DFSs have their own mechanisms to detect and correct the faults, so that users do not be aware that such fault
Facts On File, Inc., 2008. Bloom's Literature. Facts On File, Inc. Web. 11 June 2014
are put back into the directory from which they were deleted. If the file being
Goal 1: I created folders to store the major file categories used most frequently: Briefings, Remarks and Letters of Recommendation. Each folder contained subfolders, when necessary, to store the specific type of briefing (Academic Brief, Brief to Staff and Faculty, Founder’s Day Brief, etc.), remarks (Promotions, Retirements, Opening/Closing Remarks, etc.) or
Objects are the specific items being catalogued in AD DS. Common objects found in a directory are users, computers, printers, folders, and even files. These objects are grouped into containers, usually organizational units, which in turn are grouped into higher order containers themselves. An object is made up of a collection of attributes which are key-value pairs of information. An example of an attribute key would be "Given Name," and every object in the directory would have a different value for that attribute. AD DS is dynamic and extensible, which means that not all objects share the same attributes, and as an administrator we can
The purpose of preserving the data is to ensure that it can be utilized in court. If the evidence is not properly handled and protected, it might be hard for it to be admitted in the legal actions against the criminals. It is at the heart of computer forensics to collect, document, preserve and interpret the computer data. The aim of performing computer forensics is to determine who was responsible for an activity in a digital environment through a procedural investigation. In preserving the digital data, the investigators use different technologies to get access to and analyze the data in the computer systems. Preservation of data also relates to how the official data is, by analysis using various techniques and aspects. This practice needs an advanced expertise that is not conversant with the regular system users and the system support
Computer forensic experts use variety of procedure and function to identity the hard drive contents, hidden folders and unallocated disk spaces for damaged, deleted and encrypted files. These evidences are properly documents, organized and stores in the original form to actual litigation. Crucial data's are gathered from multiple sources recorded in digital form. This includes text messaging, emails, internet, tapes, disks, CD's and printouts. In the clear sense, it is used to investigate crimes directly or indirectly related to
At the outset, before the advent of user friendly operating systems, computers were run using the operating system CP/M (Control Program for Microcomputers). The program itself looked simple, but the complexity of its use meant that not many fully understood how to use it. As the program was also limited in use, since it was designed for 8-bit systems, a new operating system was needed when 16-bit IBM systems came out.
A major difficulty with the virtual machine involves disk systems. For instance, the physical machine has two disk drives but wants to support five virtual machines. The physical machine is unable to allocate a disk drive to each virtual machine because the virtual machine software itself will need substantial disk space to provide virtual memory and spooling. To solve this dilemma, virtual drives that are identical in all respects except for size are provided. The system implements each virtual disk by allocating as many tracks on the physical disks as the virtual disk needs.
other files onto a disk, which is seen in both good and bad ways, but
must be maintained in perfect order, so that any file may be located promptly by