Kids Coding

I thought I'd blogged on this before, but it seems not (at least not here!)..

When I were a nipper, I had a book on BASIC for the Acorn (BBC). Actually I had 2 books. Both very similar books, both started with something like:

10 print "hello world"
20 goto 10

But both by page 20 had started relatively advanced data-types and had all the cool programming structures of the day (gosub, etc). Both introduced peeking and poking and had simplified schematics for the 6502 and the Z80. One went off into more complex data-driven programming and the other into creating a simpl robot driven through an RS232 port. These were books for 10yr olds. I have yet to see anything similar today.

Smalltalk is kinda close, but there's something I don't like about it. Too simplified, too direct, too scripty, too much like a toy. The literature I've seen was either too condescending or too adult... in all it's designed for the classroom, not for exploration alone.

So what next? If one was to write a book, what technology? Something real, so Java or .Net based. Something with either a framework (yuck) or set of libraries to make things easier. Something accessible to kids but also something very techie. Games programming? This would be very hard to get the balance right.

Computing Paradigm

In the last few entries, I have been inexpertly trying to describe something which could represent a new(ish) paradigm in computer interaction. I kind of symbiosis of personal computing and network computing.

I feel the word 'computing' is wrong here, but I will take it to represent all things related to the layman's interpretation of what 'computing' means. So: wordprocessing is computing, email is computing, blogging is computing, M$ vs Apple is computing, memory-sticks are computing. It's a very broad term to symbolise all the things you do with the box of tricks we call a computer (including laptops, PDA's, printers, broadband, etc etc).

Personal computing is what we do with a computer when we're not on the net. We word process, store documents, edit pictures, listen to MP3's, play games (against the computer), use spreadsheets. Basically, the 1980's view of the IBM PC. It was stand-alone, operated by one person, smaller amounts of processing power, but given over to an individual.

Network computing is email, IM, surfing, blogging, VNC/WTS, SMB/file sharing. It is viewed as the modern multiple-user space where we share stuff with eachother. More than that, we share with ourselves too! It means you can have access to your personal space from anywhere in the world (for example you may keep an inbox with web-mail in it). The last thing is important - it talks about having the same information and interface available to you wherever you log into a computer. Security here is an issue, of course, but there is intrinsic value in having familiarity of interface and data.

Now, to combine the two means that personal computing should become more networky and network computing should become more personal. Some bits of technology are getting there (MySpace, MSN, Yahoo and Google have offerings that start to come close). But what I see is a method by which information and interface associated with an individual is all available from everywhere. Furthermore that information is (where appropriate) accessible regardless of where it resides. So, if I log into my computer at work, I have access to all the relevant stuff for me - personal and work related. I have access using an interface which is associated with me (why should I need to learn a new interface because my new employer decides we will all use M$ Windows 2023 with the Wibble skin and the Blahsoft document mgt system?). The same should be true when I login from home, or in an internet cafe, or wherever. Home servers should connect to intrenet-based servers and work servers seamlessly. Security would have to be cooler than cool, of course, but I'm positive that all of this is fundamentally possible.

What are computers for?

What do we use computers for then? I mean, these things are simply tools, so what's their 'thing'? Like, if you want to knock a nail in, you get a hammer. Drill a hole, the clue's in the title. But for computers it seems we focus on the wrong end - we look at the tool and say, 'what job can we do with that?'. Originally they were used, as the name suggests, for computing things - oversized calculators, basically. But now the useage profile of this tool is somewhat more fluffy. So, here are some of my thoughts on the aspects of what job computers are for (so far).

Information is clearly a big thing for computers. Information means any data that has meaning. Computers are the tools we have for manipulating information. Using computers we store it, retrieve it, edit it, perform automatic operations with it and share it around.

Perhaps it's a bit of a stretch to call that list exhaustive - I have two chat windows open right now and they fit, but only very badly into the list above. Video and voice are even more of a stretch.

However, I think this enumeration is useful to me when thinking about a holistic computer system.

Joined nodes

Scenario, based on the high level concept of PI calculus:

Nodes are joined by Channels. I contrive my Node to send my Message (a request message, requiring a response) to the target Node via one of it's public Channels. It will reply with some response Message.

Now, if I know what I want, but don't know or care where it's from, I will get my Node to go find a service Node that can answer me.

I can do this as a higher level layer over something like Java, TCP/IP, XML, etc and get something out quicker.

Objects, Types, Messages, Channels and Nodes

The thinking is like this:
Object - basic nugget of structure
Type - the introspection into an object (meta-object perhaps) says what Messages an Object recognises.
Message - a 'prod' to an object
Channel - a route for a message to get to an object
Node - martialling for messages and channels, container of objects, security

As a base for a programming language, there's too much stuff here for my liking! Also, what comes first? What's the basis of the language? Objects are the popular choice of course, but you need the other stuff.. I guess we haven't even started with any basic Types yet either, like String, Numbers, etc..

hmm..

Code is Data is Code

Last night I had a rather confused and confusing conversation with Bayard (http://blog.generationjava.com/roller/page/bayard/) regarding Code being Data and vice versa. We came to a general conclusion that it was best discussed over a beer. Still, since I opened the discussion I thought I should blog on it.

Code being Data is clear - have a look at your source files. They're structured and have meaning to the programmer.
The converse is slightly more tricky. Data (as input) is invariably interpreted by some computer process. It is a set of instructions to some process about how to proceed. Let's say we have a relational DB table called house. A house might have a number of bedrooms. The program which displays this data will make some decisions on the basis of number of bedrooms, e.g. instead of displaying "bedrooms: 0" it might say "No Bedrooms". Another clear(ish) example is in system parameters - often held in a data structure (DB table again, XML file, CSV, etc) but these clearly influence the operation of the 'interpreter' or the code.

Calling this distinction between code and data can be useful, but I believe it's an artificial boundary that can cause confusion. Where does business knowledge end and coding start?

Intrinsic environmental security

In a unix filesystem there is security on access to files and directories. This is based on rights for a user, group and world and there are read, write and execute access control for each. This works well for disk-based operating systems. A rogue process would have to be explicitly run by a particular user to have access to a particular file - for example a system configuration file requires root access.

Windows is generally less secure because file permissions aren't set in the same way (NT and XP have made some concessions to re-implementing this).

My intention is to extend this with reference to my previous post about an environment where data is held within the structure of the program. There is no file system in this situation. Access would need to be checked at runtime within the context of a thread (similar to processes being run by a particular user).

It could be checked on each function call, I don't have to say that this would have a *bit* of an overhead. Either we could accept the processor hit, or loosen the security somehow. We could make some calls unchecked, or grouping security around packages or create an override, for example the thread has been allowed to call function X, function X has stricter security than any functions it calls so no need to check security. The possibility of automating the last one here is clear.

Computer Environment

I always think the separation in application vs data storage vs operating system to be a little weird. It get weirder as you consider Ajax blurring the line between client-side application and server-side web-application (not that Ajax is particularly clever, IMO, but that's another story). The thinking goes: you run an application on the operating system. You use the application to open and manipulate data. You save your changes back into the operating system (file system). The operating system manages the file system as well as various library functions and hardware interfaces which the application might make use of. The holy trinity of desktop computing: operating system, application and data.

The thing is that this separation is wholly artificial. I admit that there is some merit in it's simplicity - as Pirsig would have it, the intellectual scalpel cuts cleanly here. The corporate advantage is that it leaves the door open for application-builders to develop their applications and sell them. However it does start to break down towards the edges, and I believe it is now really starting to show it's faults.

The downsides stem from this separation. Take auto-save as an example. The functionality was a god-send to so many who had forgotten to save when a crash had happened. The crash would wipe all data since the last save. At least auto-save would improve the frequency of making those saves. However, the auto-save was a hack to get around the separation between the operating system and the application: instead of integrating more closely with that file system we get something which, in effect, polls quicker. The problem was that the operating system hadn't supplied the libraries to help fix the problem. If the operating system was to maintain the data storage properly it must be responsible for all reads and writes. This security is crude, particularly on Windows, but even on other systems only really serves to demonstrate the separation.

I once asked a programmer friend how many interpreters he'd written - he said, 'none'. I pointed out that all programs which act upon data are interpreting it and are hence interpreters. When I asked again his answer was now, 'loads, but..', he was still unconvinced. I maintain that any data is really a set of instructions to an interpreter, we just choose to think of it the other way round - data vs application. Think about almost all modern operating systems: the programs themselves are held as files, as well as the data. It's not too hard to think of a Word document as a set of instructions which are interpreted by Word to render a document. The editor is just a fancy programming environment, further blurring the holy trinity.

There used to be lisp machines that held the whole shebang in one 'environment'. There was no operating system in any true sense, instead the systems comprised a complex web of function calls. The functions were themselves the data (at least nominally, but that's also another story), which could in turn be operated upon by other functions. Within this, 'saving' wasn't necessary because the system automatically persisted itself to whatever long-term storage medium was available as necessary, effectively the swap-disk was the long-term persistence. These systems were, on an intellectual level, a structure which the user interacted with. The blur here is almost complete - there is no difference between any part of our modern holy trinity.

There are a number of systems here which demonstrate a blurring of the sharp definitions of operating system, data and applications. I think the next step is to contemplate an environment similar to those lisp machines, but updated for today's audience.

The new environment would be a graph of 'objects', linked together and intrinsically persisted to whatever storage medium was necessary - just like the old lisp machines. Further, this environment could be networked into other systems - creating a worldwide, peer-to-peer operating system. Objects can be free to roam around this network thus moving closer to where they're used more.

To stop virii and crackers, the environment would implement security at the level of object-dispatches, passing a priviledged context in which the call is made. In old Lisp machines I'm sure the resources were not available for this, in unix and other operating systems the file system has a complex set of user permissions. This is just a step further on, inside the functionality itself.

Now, to visualise this massive amount of information, I suspect a full 3D environment would be necessary (or at least an interesting and fun idea). This would have to be created to show and hide detail as necessary depending on the level of skill of the operator. Linking environments together now becomes one of spatial geometry.

Finally, the corporate angle? Hardly the point, I know, but worth considering. Firstly, there must be objects to interface to hardware. Secondly there will be objects which can be used as user-interface artifacts (word processor, spread-sheets, etc) but remember that these interface with other objects - hence standardising all 'file formats' (which wouldn't really exist any more).

A brave new world, where there's just you and the environment. What will happen to religion then?

Apache Harmony

Apache want to create/obtain a Java VM of their very own. I've always thought about doing something like this, but that's another story. This post is about modularity in a virtual machine.

I suggested somewhere in the mailing lists that the JIT compiler could be used as the basis for writing the VM in Java. It's quite simple: the JIT converts bytecodes to native, so why not use that as the way to convert the bytecodes of a java application (the VM) into native as a one-off compilation stage. The one difficulty is memory management, but let's assume this can be overcome with some basic conventions when writing the VM.

VM server-side

Why are virtual machines so very popular on the server-side? Java was invented to be a client-side sandboxed environment. You remember all that applet rubbish that never took off?

It was actually a quite sensible idea: you can never know what hardware your client has, so the standardized interface (bytecodes, etc) made utter sense. It never took off for various reasons I don't pretend to know. I'm guessing it was a bit bulky to install, then the applets weren't exactly tiny (remember we only had 56k modems back then, some of us only had 33.6 or 28.8). Then I guess the nail in the coffin was that the applets weren't easy to visually control, so they generally looked a bit rubbish.. and if another nail were needed, Microsoft did their embrace and extend but got rebuffed.

So why did Java go all server-side? It doesn't make that much sense. The server-side hardware can be completely controlled and a virtual machine is slow compared to a compiled environment. Even JIT can't account for that much speed when compared to well-writted natively compiled code.. can it? Now .Net has arrived: the microsoft alternative to Java. Although there is a fair amount more emphasis for .Net to do GUI's, most of it is server-side and web-delivered. Folks are even doing work to other, older VM's like Lisp, ML, etc, to make them web-enabled.

The only concrete conclusion I can reach about VM's on the server is that they're just nicer languages. Nicer than C and C++ (arguably, Java is what C++ should have been). They're Garbage Collected so you can be a little lazy and not get bitten. Actually, memory leaks in non-GC environments are notoriously difficult to find and fix. You *can* create memory leaks in GC'd environments but I digress. While I'm digressing, there are non-VM based GC environments too.

I think the VM arguement is actually a red herring. I think Java got popular because it was a nicer language at the time and now it's achieved industry standard-ness.

My world

As an intro, I thought I'd write about the computers I own.

I have an old Athlon 1Ghz with 256M/80G. Basic workhorse with WinXP and Office (for CV-writing, working from home, etc). The monitor's a nice 19" Dell flatscreen. My advice to anyone buying a new computer: forget Ghz, get a great screen.

I have my Powerbook 15" G4 1.25Ghz, 512M/80G. This is my main computer - MacOSX 10.3 is a fine OS.

I have a more recent Mac Mini G4 1.4Ghz, 512M/80G. I'm using this as a home server, running MacOSX 10.3 (not OSX Server).

The mini serves files and I'm currently working on an installation of Plone/Zope to unify my address books and diaries. I could use Open-Groupware.org but it seemed much more limited, even though plone doesn't fully replace a groupware server.

The mini also serves as video-conferencing using AIM and iChat. It's interesting that there are no real cheap webcam options for Mac - I'm using my camcorder instead. This is a little annoying tho' because the Mac doesn't see the mic on this as a proper audio input device, so other VoIP applications won't use it (particularly Skype, as a friend uses this a lot).

All this runs over an 802.11g network. The positioning of my PC (upstairs) and the wireless access point means that with the belkin card I bought, it has to signal through the floor/ceiling and a chimney breast, i.e. no signal. Interesting that these cards come with an aerial in the back, which in a home you then shove up to the wall, probably in a corner. So I had to buy a separate aerial on a wire so I could move it to a better position.

Printing, I have an epson RX600. One minor gripe is that I haven't got a proper network solution for it. The 802.11g print servers are way expensive given that I'd have to walk upstairs to turn it on anyway. Not sure how to deal with this. Wonder if Epson do a plug-in network adapter which will do WoL... For now I just walk upstairs and plug in the USB cable.