I. Lesson 1

1)  Hardware and Software Differences

Computer Hardware and Software, both are essential parts of a Computer System. There are two parts to a computer system, the hardware and the other is software.

Types of Computer Hardware

• Input Devices

• Output Devices

• Storage Devices

• Internal Component
  
  

1. Input Devices: Input Devices are those devices through which a user enters data and information into the Computer or simply User can interacts with the Computer. Examples of Input Devices are Keyboard, Mouse, Scanner, etc.

2. Output Devices: Output Devices are devices that are used to show the result of the task performed by the user. Examples of Output Devices are Monitors, Printers, Speakers, etc.

3. Storage Devices: Storage Devices are devices that are used for storing data and they are also known as Secondary Storage Data. Examples of Storage Devices are CDs, DVDs, Hard Disk, Solid State Drive etc

4. Internal Component: Internal Components consists of important hardware devices present in the System. Examples of Internal Components are the CPU, Motherboard, etc.

​Types of Computer Software

• System Software

• Application Software

1. System Software: System Software is a component of Computer Software that directly operates with Computer Hardware which has the work to control the Computer’s Internal Functioning and also takes responsibility for controlling Hardware Devices such as Printers, Storage Devices, etc. Types of System Software include Operating systems, Language processors, and Device Drivers.

2. Application Software: Application Software are the software that works the basic operations of the computer. It performs a specific task for users. Application Software basically includes Word Processors, Spreadsheets, etc. Types of Application software include General Purpose Software, Customized Software, etc.

2) How DOS works?

When a computer is powered on, it goes through various steps called the boot process. For a computer running a disk operating system in the following six steps, such as:

• The boot record loads the disk operating system into memory, and it takes control of the machine.

• The computer transfers data stored on a magnetic disk into its main memory, the random access memory.

• The read only memory (ROM) bootstrap loader reads the Master Boot Record and passes control over to it.

• The computer provides various applications programming interfaces for programs like character input/output, memory management, program loading, termination, and handling input from the user through a keyboard.

• It also transfers data to external devices attached to the computer, such as a computer screen or printer.

• The OS also provides file management that organizes, reads, and writes files on storage. The files are organized in a hierarchical structure of directories, sub directories, and files.

• A disk operating system doesn't have a graphical user interface (GUI). Its interface is character-based, so users must type commands in the command line to indicate what actions they want.

3) ​Features of DOS ,What is DOS?

• DOS stands for Disk Operating System. DOS controls the computer’s hardware and provides an environment for programs to run. This system program must always be present when working with your computer.

• Here are some of the distinguishing features of a disk operating system, such as:

• A disk operating system manages files, folders and allows program loading and execution. It can control hardware devices such as disk, memory and allocate resources.

• MS-DOS offers a file system to organize, read and write files to the disk storage.

• MS-DOS does not offer GUI (Graphical User Interface) and doesn't accept mouse inputs. It is a character-based interface system where all commands are entered in the text at the command-line prompt. 

• It is a single-user operating system and performs various tasks to ensure the proper operation of systems. 

• MS-DOS does not support a multiuser operating system, and it is less secure and does not have a concept of user roles. It is very lightweight due to its basic interface and limited features.

• It uses a 16-bit file allocation table (FAT16), and a 16-bit interface is used to define the location of the memory of each file uniquely. These identifiers are stored in a tabular format with the name File Allocation table.
  
  

4) Why You Need DOS
There are a variety of reasons why you need DOS. A few of them are listed below to satisfy your curiosity.
1. DOS controls the flow of information between you and the computer (translator).
2. DOS allows you to store information on your computer.
3. DOS allows you to retrieve information stored on your computer.
4. DOS interprets and translates the software you have on your computer.
5. DOS gives you access to all its function (such as copying, saving, and printing files).

5) Limitations of MS-DOS

Here are the following limitations of the disk operating system, such as:

• 1. Built in security:DOS does not have any built in security, such as file ownership and permissions. 

  2. No multi user or multitasking:It does not support multiuser or multitasking. It can only run one program at a time, but it provides direct access to the basic I/O system and underlying hardware. 

  3. Challenging interface: An user must type in commands and remember commands to run programs and other OS tasks. For example, typing the command md \directory_name for creating a new directory and cd \directory_name for changes the current working directory to the named directory, and typing the command dir lists the files in the current directory. This approach makes it difficult for beginners to use.
     
     

6) ​Types of MS-DOS Commands

An instruction given to a computer to perform a specific task is known as a command. The MS-DOS has many commands to perform each task, and these commands are stored in the DOS directory of the disk. The MS-DOS commands are of two types, internal command, and external command.

• 3. 1. Internal Command: Internal commands are built-in commands of MS-DOS, stored in the command interpreter file (COMMAND.COM). These commands reside in memory if the system is at prompt (C:\>) level. Some of the internal commands are DATE, TIME, DIR, VER, etc.
        

     2. External Command: External commands are separate program (.com) files that reside in the DOS directory. Some of the internal commands are DATE, TIME, DIR, VER, etc. Some of the internal commands are DATE, TIME, DIR, VER, etc. 

MS-DOS is not case sensitive so that you can type commands in either uppercase or lowercase.

7) Set the Date and Time
Most computers on campus have an internal clock that will automatically set the date and time for you when you turn the computer on. However, if your computer does not have this feature or your computer has two floppy drives, you will need to do the following steps to set the date and time.
Directions:
1. Type the date like this: 08-15-2023 ( mm-dd-yyyy)
2. Press the Enter key ( return key).
3. Type the time like this: 10:15 (hh:mm)
4. Press Enter.
5. Notice that the C:\> prompt will appear.
DOS marks the date and time on everything you do. It is important to periodically check the date and time if you have an internal clock to see if it is correct. If you have a two floppy system, it is important to enter the correct date and time when you turn the computer on.
NOTE: Thats sets the date and time for you automatically when you Login.

8) Check the Date and Time
DOS will let you check or change the date and time once it has been set. The procedure to do this is as follows:
Directions:
1. Type: date and press Enter.
2. If the correct date is displayed, simply press Enter. If the date is incorrect, type the correct date and then press Enter.
3. Type: time and press Enter.
4. If the correct time is displayed, simply press return or Enter. If the time is incorrect, type the correct time and press Enter.

9) ​MS-DOS Files and Filenames

One of the primary functions of the OS is to handle disk files. A file can contain only data, or it can contain a set of instructions, called a program, telling the computer how to perform a particular task. Every file has associated with it a unique filename which is used to identify it on the disk. A filename in MS-DOS has two parts; the name and an extension.The name can contain up to eight characters. Each filename can have a three-character extension. The extension is separated from the name by a period. The period serves as a delimiter, indicating where one portion of the filename ends, and the next begins. An extension is usually used to identify files that are related in some way. MS-DOS allows the following characters to be used in a filename and extension:

• Uppercase and lowercase case letters A through Z

• Numbers 0 through 9

• Special characters $ # & @ ( ) ! ^ ` ~ { }

Any other character used in a filename, including spaces, will cause the name to be terminated at that character. It is generally good practice not to use special characters in filenames because some programs may use them as delimiters or other special purposes.

In addition, the extensions BAT, COM, EXE, and SYS have special meanings in MS-DOS and should therefore normally not be used with your data files. Shown below are examples of both valid and unacceptable filenames.

Valid MS-DOS Filenames:

• BEERSLAW

• DAT

• 1

• EXP

Valid MS-DOS Filenames:

• BEERSLAW

• DAT

• 1 

• EXP

Invalid MS-DOS Filenames:

• EXP 1.DAT (space is not allowed) 

• BEERSLAWDATA (too many characters in the name) 

• EXP1 (too many characters in the extension)

• HG>HE (> is an invalid character)