FPGA and CPLD differences

fpga cpld difference

NO .. The Architecture of a CPLD is different of a FPGA
THE FPGA is like a chess board with every square being a"CELL"
You use a synthesis tool to design .The tools does the mapping of the logic functions in a process called routing .This is very sofisticated and complex . At the end you can generate a REPORT . That will tell you if the timings concerns are met. In a general maner you don't need to worry about the underlaying structure of the FPA .. only in very particular cases when you need to optimize the timing .. FPGA have thousands of gates .. so you are never short! On the other hand a pins can be configured as either an inpur or output or both!

CLPD are diffrent .They have some pins only inputs and some pins that are both . The pins that are inputs go through a CONNECTION MATRIX
that will be programmed by some soft either low or high level description language or schematic using "PRIMITIVES" . In CPLDs you have to be more aware of the internal architecture to get the best out of it :SPEED
But the propagation times are fixed and well known !

CPLD are better to be used when you need very fast logic requirements
like memory mapping in an address bus !

Reference: http://www.edaboard.com/thread12769.html

Found some more matches in linuxquestions.org when searching for differences between ksh and bash

out of these the one by GazL is what caught my attention

Quote:

Originally Posted by jlightner  A script written to run in ksh would likely run in bash just fine. A lot of the differences deal with math, variables, arrays, functions etc... - bash just seems to have a hell of lot more of this than ksh

bash isn't always the winner. ksh has some nice useful variable typing that bash doesn't.

Code:

$ typeset -l lowercase_only
$ lowercase_only="WiBbLe"
$ echo $lowercase_only   
wibble

It's much easier than

Code:

lowercase_only=$(echo "WiBbLe" | tr "[:upper:]" "[:lower:]")

... and you don't have to keep reapplying the translation to ensure the value is lowercase should the value ever be changed. Very Useful for when dealing with user input.


I also prefer the ksh math syntax of

Code:

let a=b+c

rather than bash's more unwieldy;

Code:

a=$(( b+c ))

... but that's just a minor style thing.


The biggest difference that tends to catch people out though is this one...

ksh:

Code:

$ echo wibble | read variable
$ echo $variable
wibble
$

bash:

Code:

bash-3.1$ echo wibble | read variable
bash-3.1$ echo $variable

bash-3.1$

... Oi! bash!... where'd my variable go?
What makes this one particularly bad is that the bash code looks like it ought to work. It's only when you understand the underlying semantics of how bash deals with pipelines that you realise why it doesn't.

Because bash runs a pipeline in a sub-shell, you actually have to do it like this 

Code:

read variable < <(echo wibble)
echo $variable

mesiol also has a point

one reason for using ksh for scripting is, this shell is available on nearly all existing flavours of *nix. Bash is not installed by default on all *nix.

Difference between different shells

Hard to read here I think since the spacing is off. Here is the 
Link 

Shell features

This table below lists most features that I think would make you
choose one shell over another. It is not intended to be a definitive
list and does not include every single possible feature for every
single possible shell. A feature is only considered to be in a shell
if in the version that comes with the operating system, or if it is
available as compiled directly from the standard distribution. In
particular the C shell specified below is that available on SUNOS 4.*,
a considerable number of vendors now ship either tcsh or their own
enhanced C shell instead (they don't always make it obvious that they
are shipping tcsh.

Code:

                                     sh   csh  ksh  bash tcsh zsh  rc   es
Job control                          N    Y    Y    Y    Y    Y    N    N
Aliases                              N    Y    Y    Y    Y    Y    N    N
Shell functions                      Y(1) N    Y    Y    N    Y    Y    Y
"Sensible" Input/Output redirection  Y    N    Y    Y    N    Y    Y    Y
Directory stack                      N    Y    Y    Y    Y    Y    F    F
Command history                      N    Y    Y    Y    Y    Y    L    L
Command line editing                 N    N    Y    Y    Y    Y    L    L
Vi Command line editing              N    N    Y    Y    Y(3) Y    L    L
Emacs Command line editing           N    N    Y    Y    Y    Y    L    L
Rebindable Command line editing      N    N    N    Y    Y    Y    L    L
User name look up                    N    Y    Y    Y    Y    Y    L    L
Login/Logout watching                N    N    N    N    Y    Y    F    F
Filename completion                  N    Y(1) Y    Y    Y    Y    L    L
Username completion                  N    Y(2) Y    Y    Y    Y    L    L
Hostname completion                  N    Y(2) Y    Y    Y    Y    L    L
History completion                   N    N    N    Y    Y    Y    L    L
Fully programmable Completion        N    N    N    N    Y    Y    N    N
Mh Mailbox completion                N    N    N    N(4) N(6) N(6) N    N
Co Processes                         N    N    Y    N    N    Y    N    N
Builtin artithmetic evaluation       N    Y    Y    Y    Y    Y    N    N
Can follow symbolic links invisibly  N    N    Y    Y    Y    Y    N    N
Periodic command execution           N    N    N    N    Y    Y    N    N
Custom Prompt (easily)               N    N    Y    Y    Y    Y    Y    Y
Sun Keyboard Hack                    N    N    N    N    N    Y    N    N
Spelling Correction                  N    N    N    N    Y    Y    N    N
Process Substitution                 N    N    N    Y(2) N    Y    Y    Y
Underlying Syntax                    sh   csh  sh   sh   csh  sh   rc   rc
Freely Available                     N    N    N(5) Y    Y    Y    Y    Y
Checks Mailbox                       N    Y    Y    Y    Y    Y    F    F
Tty Sanity Checking                  N    N    N    N    Y    Y    N    N
Can cope with large argument lists   Y    N    Y    Y    Y    Y    Y    Y
Has non-interactive startup file     N    Y    Y(7) Y(7) Y    Y    N    N
Has non-login startup file           N    Y    Y(7) Y    Y    Y    N    N
Can avoid user startup files         N    Y    N    Y    N    Y    Y    Y
Can specify startup file             N    N    Y    Y    N    N    N    N
Low level command redefinition       N    N    N    N    N    N    N    Y
Has anonymous functions              N    N    N    N    N    N    Y    Y
List Variables                       N    Y    Y    N    Y    Y    Y    Y
Full signal trap handling            Y    N    Y    Y    N    Y    Y    Y
File no clobber ability              N    Y    Y    Y    Y    Y    N    F
Local variables                      N    N    Y    Y    N    Y    Y    Y
Lexically scoped variables           N    N    N    N    N    N    N    Y
Exceptions                           N    N    N    N    N    N    N    Y

Key to the table above.

   Y      Feature can be done using this shell.
          
   N      Feature is not present in the shell.
          
   F      Feature can only be done by using the shells function
          mechanism.
          
   L      The readline library must be linked into the shell to enable
          this Feature.
          
Notes to the table above

    1. This feature was not in the orginal version, but has since become
       almost standard.
    2. This feature is fairly new and so is often not found on many
       versions of the shell, it is gradually making its way into
       standard distribution.
    3. The Vi emulation of this shell is thought by many to be
       incomplete.
    4. This feature is not standard but unoffical patches exist to
       perform this.
    5. A version called 'pdksh' is freely available, but does not have
       the full functionality of the AT&T version.
    6. This can be done via the shells programmable completion mechanism.
    7. Only by specifing a file via the ENV environment variable.