In the last year much has changed in the J world.

There are new official J 8.0x builds for all supported platforms. The QT based IDE JDE has matured and is in widespread use. The column oriented J database JD is drawing new users to J and enticing J veterans to reconsider how we use databases. There is a small group of J system builders experimenting with additions, extensions and revisions of core J source code.

In short, there are have been enough changes to revisit and update JOD.

JOD version 0.9.97* is the first JOD update in many years that mocks the god of software compatibility. In particular:

The syntax of the jodhelp verb has changed. The jodsource addon no longer uses a zip file to distribute JOD dump files. JOD online help will no longer be supported or updated. Volume size is no longer checked before creating new JOD dictionaries. There is a new version of jod.pdf.

jodhelp changes (#1, #3 and #5)

jodhelp has always been a kludge. In programmer speak a kludge is some half-baked facility added to a system after more essential features have stabilized. The original versions of jodhelp pointed at my rough notes. It was all the “documentation” I needed! Then others stared using JOD which resulted in an “evolved” online version of my notes. I originally thought that hosting my notes online would simultaneously serve user needs and cut the amount of time I spent maintaining documentation. In retrospect this wasn’t even wrong!

I used Google Documents to host my notes. If you’ve ever wondered why completely free Google Documents hasn’t obliterated expensive Microsoft Word or hoary old excellent LaTeX I invite you to maintain a set of long-duration-documents with Google Documents. During jodhelp’s online lifetime the basic internal format of Google Documents changed in a screw-your-old-documents upgrade which forced me to spend days repairing broken hyper-links and reformatting. I was not amused; you still get what you pay for!

I originally choose Google Documents because of its alleged global accessibility. Sadly, Google Documents is now often blocked by corporate and national firewalls. Even when it isn’t blocked it renders like a dog peeing on a fire hydrant. All these problems forced me to rewrite JOD documentation with a completely reliable tool: good old-fashioned LaTeX. The result of my labors, jod.pdf, is now distributed by the joddocument addon and is easily browsed with jodhelp.

After jod.pdf’s appearance another irritant surfaced: synchronizing jod.pdf and the online version. I tried using pandoc and markdown to generate both the online and PDF versions from the same source files but jod.pdf is too complex for not-to-fancy portable approaches. I was faced with a choice, lower my jod.pdf standards, or get rid of something I never really liked. I opted to drown a child and abandon online help. I don’t expect a lot of mourners at the funeral.

Using the new version of jodhelp requires installing the addon joddocument and configuring a J PDF reader. It’s also good idea to define a JQT PF key to pop up JOD help with a keystroke. To configure a J PDF reader edit the configuration file:

this file is directly available from the JQT Edit\Configure menu. base.cfg defines a number of operating system dependent utilities. Make changes to the systems you use, save your changes, and restart J. The following example shows my Win64 system settings.

I use SumatraPDF to read PDF files on Windows. It’s a fast, lightweight, program that efficiently renders jod.pdf. Good PDF readers are available for all commonly used platforms.

To define JQT PK keys edit the configuration file:

This file is also directly available from Edit\Configure menu. My JOD specific PF keys are:

Pressing Shift+F3 executes jodhelp 0 which pops up JOD help.

jodsource changes (#2)

The jodsource addon is a collection of JOD dump scripts. Dump scripts are serialized versions of binary JOD dictionaries. When executed they merge objects into the current JOD put dictionary. I use them primarily to move dictionaries around but they have other uses as well. Prior to this version I distributed the three main JOD development dump scripts, joddev, jod, and utils in one compressed zip file to reduce the size of JAL downloads.

The distributed script jodsourcesetup.ijs used the zfiles addon to extract these scripts and rebuild JOD development dictionaries. This worked on 32 bit Windows systems but failed elsewhere. J now runs on 32/64 bit Windows, Mac, Linux, IOS and Android systems. To better support all these variants I eliminated the zfiles dependency and pruned the JOD development dictionaries. The result is a more portable and smaller jodsource addon.

Bye bye volume sizing (#4)

Early versions of JOD ran in the now bygone era of floppy disks. It was possible to create many JOD dictionaries on a single standard 800 kilobyte 3.5 inch floppy. Compared to modern porcine-ware JOD, which many J’ers consider a huge system, is lithe and lean. In floppy days it was important to check if there was enough space on a floppy before creating another huge 48K empty JOD dictionary. This is a bit ridiculous today! If you don’t have 48K free on whatever device you are running you have far more serious problems than not being able to create JOD dictionaries.

Volume sizing code remained in JOD for years until it started giving me problems. Returning the size of very large network volumes can be time-consuming and there are serious portability issues. Every operating system calls different facilities to return volume sizes. Even worse, security settings on corporate networks and cloud architectures sometimes refuse to divulge national secrets like free byte counts.

To eliminate all these headaches this version of JOD no longer checks volume size when the FREESPACE noun is zero. To restore the previous behavior you have to edit the file

and change the line FREESPACE=:0 to whatever byte count you want. Alternatively, you could NGAF and just assume you have 48K free on your terabyte size volumes.

Still to come

You may have surmised from JOD’s version number that the system is still not feature complete. The JOD manual lists a few words that I am planning to implement. I only develop JOD when I need something or I am bored out of my mind at work and need a break. Such intermittent motivators seldom insure project completion but I have found a new reason to finish JOD. To list a book on Goodreads or Amazon you need an ISBN number. The hardcopy version of the JOD manual is a sort-of-published book. To complete the publishing process I need an ISBN. If I am going to bother with such formalities I might as well complete the system the manual describes. So there you have it a new software development motivator: vanity.