TRICKLE
Encyclopedia
TRICKLE was a file-forwarding service on the BITNET
(EARN/NetNorth/GulfNet) network which allowed a user to request a file from an FTP server on the Internet
via a gateway server which was connected to both networks. It was intended to enable the more widespread distribution of (what was then referred to as) Public Domain software
from the SIMTEL20 and about a dozen other repositories (hence the command /PDGET, see below).
The software was originally written by Turgut Kalfaoglu at the Turkish national node TREARN (Ege University,Izmir) and was rapidly mirrored at many other BITNET nodes including AWIWUW11 (Austria), BANUFS11 (Belgium), DKTC11 (Denmark), DB0FUB11 or DTUZDV1 (Germany), IMIPOLI (Italy), EB0UB011 (Spain), TAUNIVM (Israel) and others.
To use the service, BITNET users would type a command to their local machine which would forward the remainder of the line as a command to the TRICKLE server. The syntax of the forwarded command was similar to those used on LISTSERV
but prefixed with a slash:
TELL TRICKLE AT node /PDGETfile (mode
where node was the BITNET node hosting a TRICKLE gateway; <directory>file was the directory and file required; and (mode specified the file transfer mode (eg UUE). On BITNET VAX
systems the local syntax was SEND TRICKLE@node.
The target file was conventionally divided into 64Kb chunks after zipping
and UUencoding to alleviate congestion on the BITNET network, which used a store-and-forward transmission model where files in transit were sorted into ascending order of size at each intervening node. This enabled very small files to travel reasonably quickly, leaving larger ones to queue for later (eg overnight). It was the receiving user's responsibility to piece together the chunks in order for reassembly into the full UUencoded file for decoding and unzipping.
TRICKLE used a distributed cache database - that is, it only kept one copy of each requested file in Europe and each TRICKLE server was aware of each other's files. If anyone asked for any of those files, it would be sent from whichever TRICKLE server happened to have it. This alleviated the load on the saturated international links (esp. Europe-USA) , and permitted rapid delivery of popular files. Users could also subscribe to file patterns, using a command like /SUBSCAN* for example, and each new matching file that appeared in the repository would automatically be sent to the user.
TRICKLE also had the ability to create "newsletters" and mail them out to subscribers - it contained information about each new file that was added to the repository.
TRICKLE was written in REXX programming language (over 40k lines of code) and in Assembler. It ran on IBM VM/CMS systems.
Contact: Turgut Kalfaoglu turgut (at) kalfaoglu.com
BITNET
BITNET was a cooperative USA university network founded in 1981 by Ira Fuchs at the City University of New York and Greydon Freeman at Yale University...
(EARN/NetNorth/GulfNet) network which allowed a user to request a file from an FTP server on the Internet
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
via a gateway server which was connected to both networks. It was intended to enable the more widespread distribution of (what was then referred to as) Public Domain software
Public domain software
Public domain software is software that has been placed in the public domain, in other words there is absolutely no ownership of the intellectual property that the software represents....
from the SIMTEL20 and about a dozen other repositories (hence the command /PDGET, see below).
The software was originally written by Turgut Kalfaoglu at the Turkish national node TREARN (Ege University,Izmir) and was rapidly mirrored at many other BITNET nodes including AWIWUW11 (Austria), BANUFS11 (Belgium), DKTC11 (Denmark), DB0FUB11 or DTUZDV1 (Germany), IMIPOLI (Italy), EB0UB011 (Spain), TAUNIVM (Israel) and others.
To use the service, BITNET users would type a command to their local machine which would forward the remainder of the line as a command to the TRICKLE server. The syntax of the forwarded command was similar to those used on LISTSERV
LISTSERV
LISTSERV was the first electronic mailing list software application, consisting of a set of email addresses for a group in which the sender can send one email and it will reach a variety of people...
but prefixed with a slash:
TELL TRICKLE AT node /PDGET
where node was the BITNET node hosting a TRICKLE gateway; <directory>file was the directory and file required; and (mode specified the file transfer mode (eg UUE). On BITNET VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...
systems the local syntax was SEND TRICKLE@node.
The target file was conventionally divided into 64Kb chunks after zipping
ZIP (file format)
Zip is a file format used for data compression and archiving. A zip file contains one or more files that have been compressed, to reduce file size, or stored as is...
and UUencoding to alleviate congestion on the BITNET network, which used a store-and-forward transmission model where files in transit were sorted into ascending order of size at each intervening node. This enabled very small files to travel reasonably quickly, leaving larger ones to queue for later (eg overnight). It was the receiving user's responsibility to piece together the chunks in order for reassembly into the full UUencoded file for decoding and unzipping.
TRICKLE used a distributed cache database - that is, it only kept one copy of each requested file in Europe and each TRICKLE server was aware of each other's files. If anyone asked for any of those files, it would be sent from whichever TRICKLE server happened to have it. This alleviated the load on the saturated international links (esp. Europe-USA) , and permitted rapid delivery of popular files. Users could also subscribe to file patterns, using a command like /SUB
TRICKLE also had the ability to create "newsletters" and mail them out to subscribers - it contained information about each new file that was added to the repository.
TRICKLE was written in REXX programming language (over 40k lines of code) and in Assembler. It ran on IBM VM/CMS systems.
Contact: Turgut Kalfaoglu turgut (at) kalfaoglu.com