Functions Of A Basic Assembler

Published Date: 02 Nov 2017

MIS (management information systems) is a general term for the computer systems in an enterprise that provide information about its business operations. It's also used to refer to the people who manage these systems. Typically, in a large corporation, "MIS" or the "MIS department" refers to a central or centrally-coordinated system of computer expertise and management, often including mainframe systems but also including by extension the corporation's entire network of computer resources.

, System software is the class of program that controls and supports the computer hardware and its information processing activities. Basically, system software can grouped into 3 major functional categories and discuss it accordingly.

System software is the files and programs that make up computer’s operating system. The system software are Window Xp, Window 7 32 or 64bit, and the latest Window 8 32 or 64bit are part of the operating system that have nowadays. These system software will lets user can control the hardware perfectly and get a smooth performance as well to done their stuff. The system files that come with the system software include libraries of functions, system services, drivers for printers and other hardware, system preferences, and other configuration files. The program that come with system software are assemblers, compilers, file management tools, system utilities, and debuggers.

The system software is installed on computer when user install the operating system. The operating system can update anytime by clicking the "Window Update" buttons for Windows or "Software Update" for Mac OS X inside the program files. This make your computer always up to date and running well. For example, to make the operating system and hardware started most important drivers is BIOS. It gets the computer system started and manage the data flow between the operating system and attached devices such as hard disk, video adapter, keyboard, mosue, and printer. Next, the boot program loads the operating system into computer’s main memory or random access memory (RAM). Follow by assembler takes basic computer instructions and converts them into a pattern of bits that the computer’s processor can use to perform its basic operations. Lastly, the device driver control some device that attached to the computer such as mouse and keyboard. With this all step user can use it more perfectly.

Operating System

An operating system is a program designed to run other programs on a computer. A computer’s operating system is its most important program. It is considered the backbone of a computer, managing both software and hardware resources. Operating systems are responsible for everything from the control and allocation of memory to recognizing input from external devices and transmitting output to computer displays. They also manage files on computer hard drives and control peripherals, like printers and scanners.

The operating system of a large computer system has even more work to do. Such operating systems monitor different programs and users, making sure everything runs smoothly, without interference, despite the fact that numerous devices and programs are used simultaneously. An operating system also has a vital role to play in security. Its job includes preventing unauthorized users from accessing the computer system.

Operating systems can be classified as follows

Multi-user: Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.

Multiprocessing : Supports running a program on more than oneCPU.

Multitasking : Allows more than one program to run concurrently.

Multithreading : Allows different parts of a single program to run concurrently.

Real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, andWindows, but others are available, such as Linux.

Assembly

Assembly is system software which is used to convert an assembly language program to its equivalent object code. The input to the assembler is a source code written in assembly language and the output is the object code. The design of an assembler depends upon the machine architecture as the language used is mnemonic language.

Functions of a Basic Assembler

- Convert mnemonic operation codes to their machinelanguage equivalents

E.g. STL -> 14 (line 10)

- Convert symbolic operands to their equivalent machine addresses

E.g. RETADR -> 1033 (line 10)

- Build the machine instructions in the proper format

Convert the data constants to internal machinerepresentations

E.g. EOF -> 454F46 (line 80)

Write the object programand the assembly listing

Assembler Directives

Assembler directives are Pseudo-instructions that are not translated intomachine instructions and they provide instructions to the assembler itself.

The SIC assembler directives.

START

- Specification of the name and start address of the program.

END

- Indication of the end of the program and optionally the address of the first executable instruction.

BYTE

- Declaration of character or string constants.

WORD

- Declaration of integer constants.

RESB

- Declaration of character variables or arrays.

RESW

-Declaration of integer variables or arrays

Compiler

A compiler is a special program that processes statements written in a particular programming language and turns them into machine language or "code" that a computer'sprocessor uses. Typically, a programmer writes language statements in a language such as Pascal or C one line at a time using an editor . The file that is created contains what are called the source statements . The programmer then runs the appropriate language compiler, specifying the name of the file that contains the source statements.

When executing (running), the compiler first parses (or analyzes) all of the language statements syntactically one after the other and then, in one or more successive stages or "passes", builds the output code, making sure that statements that refer to other statements are referred to correctly in the final code. Traditionally, the output of the compilation has been called object code or sometimes anobject module . (Note that the term "object" here is not related to object-oriented programming .) The object code ismachine code that the processor can process or "execute" one instruction at a time.

Utility Software

Utility Software is a type of computer system software also referred to as service program, tool, service routine, or utility routine. Software Utilities are specifically designed to help the end-user manage and tune the computer hardware/Software, Operating system or application software and perform as single precise task as opposed to application software which performs multi-tasking. Utility software can be seen in many operating systems to day e.g. Windows XP, Windows Vista, Mac OS X etc. Examples of some of the commonly used utility software may include the following; Disk Defragmentation System,

Disk Defragmentation System

Defragmentation is the process of locating the noncontiguous fragments of data into which a computer file may be divided as it is stored on a hard disk, and rearranging the fragments and restoring them into fewer fragments or into the whole file. Defragmentation reduces data access time and allows storage to be used more efficiently. Some operating systems automatically defragment storage periodically; others require that the user occasionally use a special utility for this purpose. Windows 98 comes with a built-in defragmenter as a "system tool" that the user can run. Windows NT did not come with a defragmenter because its file system, NTFS, was designed to minimize fragmentation; however, NT users often find one necessary and several vendors provide defragmenters. Windows 2000 comes with a "light" version of the Diskeeper defragmenter; some users (especially corporate users) use Diskeeper or some other full-function defragmentation program to manage storage efficiency and performance. Windows XP comes with a utility called "Disk Defragmenter."

File archiver

A file archiver is a computer program that combines a number of files together into one archive file, or a series of archive files, for easier transportation or storage. Many file archivers employ archive that provide lossless data compression to reduce the size of the archive which is often useful for transferring a large number of individual files over a high latency network like the Internet.

The most basic archivers just take a list of files and concatenate their contents sequentially into the archive. In addition the archive must also contain some information about at least the names and lengths of the originals, so that proper reconstruction is possible.

Conclusion

The system software is installed on computer when user install the operating system. The operating system can update anytime by clicking the "Window Update" buttons for Windows or "Software Update" for Mac OS X inside the program files. This make your computer always up to date and running well.

In question 1, had discuss there are operating system, Assembler Directives, compiler, utility software and other as well. A computer’s operating system is its most important program. It is considered the backbone of a computer, managing both software and hardware resources. Operating systems are responsible for everything from the control and allocation of memory to recognizing input from external devices and transmitting output to computer displays.

Introduction

MIS (management information systems) is a general term for the computer systems in an enterprise that provide information about its business operations. It's also used to refer to the people who manage these systems. Typically, in a large corporation, "MIS" or the "MIS department" refers to a central or centrally-coordinated system of computer expertise and management, often including mainframe systems but also including by extension the corporation's entire network of computer resources.

The Open Systems Interconnect (OSI) model has seven layers. In the OSI model, data communication starts with the top layer at the sending side, travels down the OSI model stack to the bottom layer, then traveses the network connection to the bottom layer on the receiving side, and up its OSI model stack.

Question 2

The OSI model defines internetworking in terms of a vertical stack of seven layers. The upper layers of the OSI model represent software that implements network services like encryption and connection management. The lower layers of the OSI model implement more primitive, hardware-oriented functions like routing, addressing, and flow control.

In the OSI model, data communication starts with the top layer at the sending side, travels down the OSI model stack to the bottom layer, then traveses the network connection to the bottom layer on the receiving side, and up its OSI model stack.

PHYSICAL LAYER

The physical layer, the lowest layer of the OSI model, is concerned with the transmission and reception of the unstructured raw bit stream over a physical medium. It describes the electrical/optical, mechanical, and functional interfaces to the physical medium, and carries the signals for all of the higher layers. It provides:

Data encoding: modifies the simple digital signal pattern (1s and 0s) used by the PC to better accommodate the characteristics of the physical medium, and to aid in bit and frame synchronization. It determines:

What signal state represents a binary 1

How the receiving station knows when a "bit-time" starts

How the receiving station delimits a frame

Physical medium attachment, accommodating various possibilities in the medium:

Will an external transceiver (MAU) be used to connect to the medium?

How many pins do the connectors have and what is each pin used for?

Transmission technique: determines whether the encoded bits will be transmitted by baseband (digital) or broadband (analog) signaling.

DATA LINK LAYER

The data link layer provides error-free transfer of data frames from one node to another over the physical layer, allowing layers above it to assume virtually error-free transmission over the link. To do this, the data link layer provides: 

Link establishment and termination: establishes and terminates the logical link between two nodes.

Frame traffic control: tells the transmitting node to "back-off" when no frame buffers are available.

Frame sequencing: transmits/receives frames sequentially.

Frame acknowledgment: provides/expects frame acknowledgments. Detects and recovers from errors that occur in the physical layer by retransmitting non-acknowledged frames and handling duplicate frame receipt.

Frame delimiting: creates and recognizes frame boundaries.

Frame error checking: checks received frames for integrity.

Media access management: determines when the node "has the right" to use the physical medium.

NETWORK LAYER

The network layer controls the operation of the subnet, deciding which physical path the data should take based on network conditions, priority of service, and other factors. It provides: 

Routing: routes frames among networks.

Subnet traffic control: routers (network layer intermediate systems) can instruct a sending station to "throttle back" its frame transmission when the router's buffer fills up.

Frame fragmentation: if it determines that a downstream router's maximum transmission unit (MTU) size is less than the frame size, a router can fragment a frame for transmission and re-assembly at the destination station.

Logical-physical address mapping: translates logical addresses, or names, into physical addresses.

Subnet usage accounting: has accounting functions to keep track of frames forwarded by subnet intermediate systems, to produce billing information.

Communications Subnet

The network layer software must build headers so that the network layer software residing in the subnet intermediate systems can recognize them and use them to route data to the destination address. 

This layer relieves the upper layers of the need to know anything about the data transmission and intermediate switching technologies used to connect systems. It establishes, maintains and terminates connections across the intervening communications facility (one or several intermediate systems in the communication subnet). 

TRANSPORT LAYER

The transport layer ensures that messages are delivered error-free, in sequence, and with no losses or duplications. It relieves the higher layer protocols from any concern with the transfer of data between them and their peers. 

The size and complexity of a transport protocol depends on the type of service it can get from the network layer. For a reliable network layer with virtual circuit capability, a minimal transport layer is required. If the network layer is unreliable and/or only supports datagrams, the transport protocol should include extensive error detection and recovery. 

The transport layer provides:

Message segmentation: accepts a message from the (session) layer above it, splits the message into smaller units (if not already small enough), and passes the smaller units down to the network layer. The transport layer at the destination station reassembles the message.

Message acknowledgment: provides reliable end-to-end message delivery with acknowledgments.

Message traffic control: tells the transmitting station to "back-off" when no message buffers are available.

Session multiplexing: multiplexes several message streams, or sessions onto one logical link and keeps track of which messages belong to which sessions (see session layer).

Typically, the transport layer can accept relatively large messages, but there are strict message size limits imposed by the network (or lower) layer. Consequently, the transport layer must break up the messages into smaller units, or frames, prepending a header to each frame

Session Layer

The session layer controls the dialogues (connections) between computers. It establishes, manages and terminates the connections between the local and remote application. It provides for full-duplex, half-duplex, or simplex operation, and establishes check pointing, adjournment, termination, and restart procedures. The OSI model made this layer responsible for graceful close of sessions, which is a property of the Transmission Control Protocol, and also for session checkpointing and recovery, which is not usually used in the Internet Protocol Suite. The session layer is commonly implemented explicitly in application environments that use remote procedure calls.

Presentation Layer

The presentation layer establishes context between application-layer entities, in which the higher-layer entities may use different syntax and semantics if the presentation service provides a mapping between them. If a mapping is available, presentation service data units are encapsulated into session protocol data units, and passed down the stack.

This layer provides independence from data representation (e.g., encryption) by translating between application and network formats. The presentation layer transforms data into the form that the application accepts. This layer formats and encrypts data to be sent across a network. It is sometimes called the syntax layer.

The original presentation structure used the Basic Encoding Rules of Abstract Syntax Notation One (ASN.1), with capabilities such as converting an EBCDIC-coded text file to an ASCII-coded file, or serialization of objects and other data structures from and to XML.

Application Layer

The application layer is the OSI layer closest to the end user, which means that both the OSI application layer and the user interact directly with the software application. This layer interacts with software applications that implement a communicating component. Such application programs fall outside the scope of the OSI model. Application-layer functions typically include identifying communication partners, determining resource availability, and synchronizing communication. When identifying communication partners, the application layer determines the identity and availability of communication partners for an application with data to transmit. When determining resource availability, the application layer must decide whether sufficient network or the requested communication exists. In synchronizing communication, all communication between applications requires cooperation that is managed by the application layer.

CONCLUSION

Short for Open System Interconnection, an ISO standard for worldwide communications that defines a networking framework for implementing protocols in seven layers. Control is passed from one layer to the next, starting at the application layer in one station, proceeding to the bottom layer, over the channel to the next station and back up the hierarchy.

The Open Systems Interconnect (OSI) model has seven layers. This article describes and explains them, beginning with the 'lowest' in the hierarchy (the physical) and proceeding to the 'highest' (the application). The layers are stacked this way:

Application

Presentation

Session

Transport

Network

Data Link

Physical

According the question requirement, I had answer all and the answer is at above about the 7 layer of OSI.