TACL
Encyclopedia
TACL is the scripting programming language used in Tandem Computers
. TACL is the shell.
Tandem Computers were originally designed and sold by Tandem Computers, Inc., based in Cupertino, CA. These were the first commercially available parallel processing computers, originally referred to as "mini-computers". Tandem's strategy was the emerging concept of "continuous availability" that relied on redundant hardware and software, and a well engineered operating system (NonStop Kernel or NSK) to ensure continuous application availability by ensuring the system could survive any single point of hardware failure. The company was bought out in 1999 by Compaq Computers, and several years later by Hewlett Packard Computers. Today they are known as "HP Nonstop", see below link to the new HP Integrity NonStop Blade systems:
http://h20223.www2.hp.com/nonstopcomputing/cache/595857-0-0-224-121.html
Each pair of CPUs, 0 and 1 for example, share hardware ownership, like disk drives, and that makes them redundant or NonStop. For example if cpu 0 fails, then cpu 1 takes over ownership of a disk drive, thus giving redundancy. There is also software redundancy built in. A primary process that is running may be given a backup process, which receives checkpoint information. If the primary process fails, through whatever reason, the backup process takes over, starting another backup process. This is what earned them the name Nonstop, since application programs can be fault-tolerant. This makes them very attractive for their customers, because of their ability for continuous availability, or being NonStop. These systems are also known for handling very high numbers of transactions per second, which is very useful for banks and stock exchanges.
http://docs.hp.com/en/NSGSeries.html
The paragraph above describes the philosophy behind the design of the hardware and the software. Upon that NSK platform there are two programming languages at least - TAL
as the compiled language, and TACL as the interpreted language. NSK has compilers for most useful languages too. TAL is rumoured to be about to be deprecated, but TACL remains as the default scripting language on these machines. HP provide a Korn-based shell command interface also these days, but it does not offer all that TACL does for NSK sysadmins - for instance, the netstat command has not been implemented. TACL builtins reflect the multi-CPU nature of NSK, and there probably isn't much more to say than that - if you fully understand all the TACL builtins then you are probably well on the way to understanding the NSK.
TACL continues to be the scripting language used on Hewlett Packard NonStop Servers. NonStop servers are key components of the backbone infrastructure of the largest banks, casinos, retailers, telephone companies, email systems, and stock exchanges worldwide.
TACL is interpreted. TACL instructions can be stored in a simple text file as MACROS, ROUTINES, or DEFINES to make scripts. Such scripts are often used to store complex configuration instructions such as start-up and hardware configuration sequences.
The TACL language has a large number of Built-in utilities which allow the user to capture output from various system utilities and parse the captured text, line by line or character by character. This allows users to build TACL programs that can monitor system events through the use of filters that monitor the system and application event logs.
Example of a TACL routine saved in the file FILE1:
?Section HELLO_BERNARD ROUTINE
# OUTPUT Hello BERNARD
How to run the TACL routine:
1. From a TACL prompt type: LOAD / KEEP 1 / FILE1 (this loads the routine into memory)
2. Type: HELLO_BERNARD to run the routine
3. Output will be: Hello BERNARD
Or create a file named FILE1 and add the following two lines:
?TACL ROUTINE
# OUTPUT Hello BERNARD
Execute the routine by naming the file at the tacl prompt:
> RUN FILE1
Tandem Computers
Tandem Computers, Inc. was the dominant manufacturer of fault-tolerant computer systems for ATM networks, banks, stock exchanges, telephone switching centers, and other similar commercial transaction processing applications requiring maximum uptime and zero data loss. The company was founded in...
. TACL is the shell.
Tandem Computers were originally designed and sold by Tandem Computers, Inc., based in Cupertino, CA. These were the first commercially available parallel processing computers, originally referred to as "mini-computers". Tandem's strategy was the emerging concept of "continuous availability" that relied on redundant hardware and software, and a well engineered operating system (NonStop Kernel or NSK) to ensure continuous application availability by ensuring the system could survive any single point of hardware failure. The company was bought out in 1999 by Compaq Computers, and several years later by Hewlett Packard Computers. Today they are known as "HP Nonstop", see below link to the new HP Integrity NonStop Blade systems:
http://h20223.www2.hp.com/nonstopcomputing/cache/595857-0-0-224-121.html
Each pair of CPUs, 0 and 1 for example, share hardware ownership, like disk drives, and that makes them redundant or NonStop. For example if cpu 0 fails, then cpu 1 takes over ownership of a disk drive, thus giving redundancy. There is also software redundancy built in. A primary process that is running may be given a backup process, which receives checkpoint information. If the primary process fails, through whatever reason, the backup process takes over, starting another backup process. This is what earned them the name Nonstop, since application programs can be fault-tolerant. This makes them very attractive for their customers, because of their ability for continuous availability, or being NonStop. These systems are also known for handling very high numbers of transactions per second, which is very useful for banks and stock exchanges.
http://docs.hp.com/en/NSGSeries.html
The paragraph above describes the philosophy behind the design of the hardware and the software. Upon that NSK platform there are two programming languages at least - TAL
TAL
-Abbreviation:*TAL effector, a family of DNA binding proteins with high sequence specificity*Ralph M. Calhoun Memorial Airport , in Tanana, Alaska*The Alberta Library*The programming languages:**Typed assembly language...
as the compiled language, and TACL as the interpreted language. NSK has compilers for most useful languages too. TAL is rumoured to be about to be deprecated, but TACL remains as the default scripting language on these machines. HP provide a Korn-based shell command interface also these days, but it does not offer all that TACL does for NSK sysadmins - for instance, the netstat command has not been implemented. TACL builtins reflect the multi-CPU nature of NSK, and there probably isn't much more to say than that - if you fully understand all the TACL builtins then you are probably well on the way to understanding the NSK.
TACL continues to be the scripting language used on Hewlett Packard NonStop Servers. NonStop servers are key components of the backbone infrastructure of the largest banks, casinos, retailers, telephone companies, email systems, and stock exchanges worldwide.
TACL is interpreted. TACL instructions can be stored in a simple text file as MACROS, ROUTINES, or DEFINES to make scripts. Such scripts are often used to store complex configuration instructions such as start-up and hardware configuration sequences.
The TACL language has a large number of Built-in utilities which allow the user to capture output from various system utilities and parse the captured text, line by line or character by character. This allows users to build TACL programs that can monitor system events through the use of filters that monitor the system and application event logs.
Example of a TACL routine saved in the file FILE1:
?Section HELLO_BERNARD ROUTINE
How to run the TACL routine:
1. From a TACL prompt type: LOAD / KEEP 1 / FILE1 (this loads the routine into memory)
2. Type: HELLO_BERNARD to run the routine
3. Output will be: Hello BERNARD
Or create a file named FILE1 and add the following two lines:
?TACL ROUTINE
Execute the routine by naming the file at the tacl prompt:
> RUN FILE1