When the term open-source is mentioned the idea of Linux immediately comes to mind but did you know that open-source started with the IBM Mainframes (yes the dinosaurs of the computing industry) back in the mid 1950's. That was when several large companies joined together to start the SHARE user group to help them better use their IBM 7090/7094 computers. They developed, and shared, tools and operating system enhancements freely. Over time, as more computers were installed, the sharing continued and expanded across the different computer brands and operating systems while the SHARE community continued to share their open-source. Some called it shareware at the time but that term was picked up by the home computer crowd in the late 1970's and 1980's while in the mainframe community there are mod tapes from various local user groups and from both SHARE and G.U.I.D.E. In the late 1970's Arnold Casinghino, while working at the Connecticut Bank and Trust, received his employers permission and he began the CBT Tape on which he consolidated many of the mod tapes that he then shared at the SHARE conferences (and via the mail). The contents of this tape included user modifications to the IBM operating system (MFT/MVT) and utilities such as tape mapping, disk mapping, smf reporting, file copy, and more - tools which IBM didn't provide or if they did it wasn't adequate.
In 1990 Sam Golob picked up management of the CBT Tape and shepherded its transition to the web where we find it today. No more tapes - just downloadable files. The contents also aged well by incorporating mods and utilities for OS/VS1, OS/VS2, MVS, MVS/SP, MVS/XA, OS/390, and now z/OS. During this time the number of files grew from a few hundred to now over 1,000 files - files which range from individual tools to files with dozens of tools. And these files are still being updated and enhanced by contributors around the globe, with new contributions joining the tape over the course of a year.
To check out this great resource for the z/OS environment point your browser to https://cbttape.org and then on the left side of the page click on CBT or Updates. The Updates page contains those files that have been updated since a virtual tape was cut. That happens a few times a year to merge all the updated files into the main tape.
These files are all in zip format to save space and within each file is either a data or xmit file. Just download to your system of choice and unzip to get started.
The data is a sequential file that is just text, most of these files are information about the contents of the tape or JCL used in the management of the tape and they can be used immediately after uploading, in binary since the data is in the EBCDIC character set, to your z/OS system into a dataset with RECFM=FB,LRECL=80,BLKSIZE=23440.
The xmit files are files created using the TSO command transmit (alias xmit) which converts a partitioned dataset into an encoded sequential file for each transfer off of the z/OS system. Transfer to your z/OS system, in binary, to your z/OS system into a dataset with RECFM=FB,LRECL=80,BLKSIZE=23440. Then issue the TSO receive command to convert the file into a partitioned dataset. Just follow the prompts on the command and you'll be fine. The xmit file can now be deleted if you like.
There are two types of partitioned datasets, the most common are those with source code, the other is a load library with executable load modules.
File 001 is the place to start as it has information on all of the files, along with information about how the tape was created. Within each source code partitioned dataset is typically a member that starts with @FILEnnn or @FILnnnn that contains more information about the contents of the partitioned dataset. Many of the files also have a README or INSTALL member with instructions on how to install the tools within the partitioned dataset for use - in come cases including the JCL and source code to compile/assemble, link, and then execute.
If you have the ability check out the CBTView application found in File 43 which is a full ISPF dialog application to easily access the CBT Tape files from your z/OS system. It makes it easy to download the files directly to z/OS along with a way to easily search for the tool you are interested in.
I hope this short blog helps you to better understand the open-source available for the z/OS eco-system. There is a lot more such as the zopen community where you can find open-source tools that run in the z/OS UNIX (OMVS) environment such as git, sudo, mandb, grep, and more (currently 225 repositories).