Tutorial By Namitha

               In the microprogrammed control units all the control signals associated with microoperations are stored in special memory called control memory .           Set of control signals that cause microoperations to occur is called microinstructions .           Micro-programmed control unit can be classified into two types based on the type of Control Word(microinstructions) stored in the Control Memory .  Horizontal micro-programmed control unit   Vertical micro-programmed control unit In  Horizontal micro-programmed  control unit, the control signals are represented in the decoded binary format .                     ‘n ’ control signals require n bit encoding i.e., 1 bit/CS .  In  Vertical micro-programmed   control unit, the control signals are repres...

A digital computer consists of CPU , a memory and I/O devices . CPU can be classified into two distinct but interactive fu nctional units    1)  Processing section (Processor)                               2) Control Section Microprogram sequencer is a convenient element for constructing a microprogram control for CPU .  Microprogrammed Computer consists of a  Memory unit ,two processor unit , a microprogram sequencer ,a control memory and few other digital functions . The memory unit stores the instructions and data supplied by the user through an input device .

A microprogram control unit consists of two parts : 1 ) Control Memory that stores the microinstructions 2) Associated circuits that control the generation of the next address . The address generation part is sometimes called a microprogram sequencer ,since it sequences the microinstructions in control memory .   T ypical sequencer provides the following address-sequencing capabilities : 1.Increments the present address for control memory .    Sequential access: The content of address register of the control memory (CAR) is    incremented after execution of each micro-instruction . 2. Branches to an address as specified by the address field of the microinstruction. 3 . Branches to a given address if a specified status bit equal to 1. 4.Transfer control to a new address as specified by an external source .   The external address transfers control to the first microinstruction in a microprogram . 5 .Support subroutine call ...

Control Memory In a micro-program control, the control variables that initiate micro-operations are stored in memory called control memory. •The control memory is a ROM, since the control sequence is permanent and needs no alteration. Micro instructions The word stored in the control memory are micro-instructions. Each micro-instruction specifies one or more micro-operations for the components in the system. 

Normalisationis a process of organizing the data in database to avoid data redundancyand anomalies . We have different levels of normal forms 1st,2nd, 3rd , BCNF ,4th,5th etc . A relation is always specified with its highest normalization level . First Normal Form defines that all the attributes in a relation must have atomic values . Second Normal Form is based on the concept of fully functional dependency . To be in second normal form, a relation must be in First Normal Form and every non-prim attributes are fully functionally dependent on any of the candidate keys. A relation is in 3rd normal form , 1)It must be in 2NF 2)Nonprime attributes should not be transitively dependent on candidate keys. For a relation to be in Boyce-CoddNormal Form (BCNF  or 3.5 NF) , 1.It should be in theThird Normal Form. 2.And, for any dependency X→ Y, X must be asuper key. Stronger version of 3NF .

A minimal cover of a set of FDs F is a minimal set of functional dependencies F min  that is equivalent to F. There can be many such minimal covers for a set of functional dependencies F. Steps to derive  minimal cover for  a FD set . 1)Right Hand Side (RHS) of all FDs should be single attribute . 2)Eliminate redundant functional dependencies if any . Given relation R(A,B,C)    and      FDs : {  AB -> C, C -> A }    FDmin ={AB à C}   ,here C-->A is   redundant dependency  3)Remove redundant attribute on LHS if any .  Consider  FD ,  AB -> C              If AB+ = A+  we can say B is redundant  then reduce to  A à C              If AB+ =B+ we can say A is redundant then reduce to B à C

You will be given a relation (R) with different functional dependency sets X,Y of that relation , you need to check whether one functional dependency is a subset of other (X⊇Y/ Y"⊇"X ) or both are equal (X=Y).   Consider X and Y are two FD sets for a relation R ,   1)If all FDs of X can be determined from FDs that are present in Y , we can conclude that  Y  ⊇   X    or X ⊆ Y    (Y covers X)  .   2)If all FDs of Y can be determined from FDs that are present in X , we can conclude         X ⊇ Y   or Y ⊆ X (X covers Y) . 3) If   1 and 2 are satisfied   then ,we can say   X=Y  or X and Y are equivale nt .

Attribute Closure:   Attribute closure of an attribute set can be defined as set of attributes which can be functionally determined from it . To find attribute closure of an attribute set: Add elements of attribute set to the closure set. Recursively add elements to the closure set which can be functionally determined from the present elements of the closure   set . Attribute closure of an attribute set A of given relation R can be represented as A +

Redundancy in relation may cause insertion, deletion and updation anomalies Normalization  is the process of minimizing  redundancy  from a relation or set of relations . I t helps to minimize the redun dancy in relations , hence avoids anomalies . A functional dependency (FD) for relation R is a formula of the form A à B where A and B are sets of attributes of R. We say A functionally determines the B , or   B   is functionally dependent on the A . Trivial functional dependency :  A → B has trivial functional dependency if B is a subset of A . Non Trivial Functional Dependency : If a functional dependency X->Y holds , where Y is not a subset of X then this dependency is called non trivial Functional dependency . Multi valued   dependency   :   occurs when two attributes in a table are independent of each other but, both depend on a third attribute . Transitive dependency:    functional dependency  is said to b...

A poorly designed database is inconsistent and create issues while adding, deleting or updating information . Poorly designed database stores same data item multiple times , known as Data Redundancy .

Key has important role in relational database:   I t is used for identifying unique rows from table. It  establishes relationship among tables . Types of keys : Composite keys ,Super keys , candidate keys, primary key, secondary keys , Composite Key :   A key that consists of more than one attribute to uniquely identify rows (also known as records & tuples) in a table is called composite key . Super Key  :   A super key is a set of one of more attributes to uniquely identify rows in a table . Candidate Key  :   A minimal  super key with no redundant attributes . Primary key:   A Primary key is selected from a set of candidate keys .   This is done by database admin or database designer.  Foreign Key   :  Foreign keys are the attributes of a table that points to the primary key of another table. They act as a cross-reference between tables .

CONTROL LOGIC DESIGN 

Arithmetic Circuit Design Examples 

Design Of Logic circuit

Register Transfer Logic & Arithmetic Unit Design

CACHE MEMORY BASICS  & CACHE MAPPING FUNCTIONS WITH EXAMPLES 

Memory System ,Memory hierarchy

SCSI BUS   ,PCI BUS  ,USB   

I/O ORGANISATION

 Basic Processing Unit   Single bus organisation & Multiple bus organisation  Instruction Execution Arithmetic Algorithms Floating point Representation 

We can start learning basics of Computer Organisation & Architecture  .  Understand the difference between computer architecture & organisation first . BASIC OPERATIONAL CONCEPTS  We can discuss about various operations used for transferring and manipulating data BUS STRUCTURE We can consider definition of BUS also about way of transferring data through Bus . MEMORY LOCATIONS & ADDRESSING Understand the basics of System Memory ,way of storing data in memory.  W can discuss here about memory addresses and about Byte addressable memory .At the end we will get the idea about memory size specification and how to calculate the address of memory bytes . INSTRUCTION EXECUTION &STRAIGHT LINE SEQUENCING Understand what an instruction is ,then learn about how to complete the execution of a program which is present in main memory of the system by executing set of instructions one after another . Here consider , two situations of instruction executi...

SUBROUTINE &STACK       In  a given program ,it is often necessary to perform a particular task many times on  different  data values . When a program branches to a subroutine, we say that it is calling the  subroutine . The instruction that performs the branch operation is called a call_subroutine   instruction. After a subroutine has been executed, subroutine is said to return to the program  that called it   by executing a Return instruction . T he calling program must resume  execution  , continuing   immediately after the instruction that called the subroutine. Call subroutine is a special branch instruction that performs the following operations • store the contents of the PC in the link register (LR) • branch to the target address specified by the instruction The return from a subroutine branches to the address contained in the link register . Subroutine Nesting and The Processor Stack When ...