Screens Environment is a multi-platform component based middleware research project designed to connect technologies together and provide better user experiences for the future of computing http://sourceforge.net/projects/screensos/
Wednesday, March 30, 2005
Update
Finished coding all functions in the PrivateData component apart from Resize and Align which while are not needed at the moment will be coded after CoreItem is coded (because CoreArray uses it).
I have added a new feature to the CoreItem design which are called Temporary Items. The difference between a temporary item and a normal item is that once a normal item is removed, its handle now points to an empty item and the handle will never be used by another item. Temporary items once they are removed can have thier handle be used by another allocation. If you create a temporary item, you must make sure that the handle is not used or stored once its removed otherwise you might point to another item by mistake. Temporary items are used for either tightly controlled items (like the file item of an object) or quick/temporary uses.
So I have CoreItem to code now which is going to probably take quite a while. Its a complex component but provides great uses once its finished. Then we have CoreArray which basicly takes an item and allows to store an array of structures together one after each other but unlike C/C++ arrays, the array is dynamic.
I really feel the progress coming forward. I dont see myself recoding what I have coded so far, so I see this as the final code (not demo code).
Thursday, March 24, 2005
Blog... Blog... Blog...
So I found last night what was causing headache while coding... Offset calculations
The PrivateData component takes the stream provided by the PrivateDisk (previous) component and splits it into allocations called 'Data'. Each Data is allocated after the last data allocation so even if data is removed anywhere but the last data does not regain allocation free space. That space is regained by aligning all data to the start (overwriting free space). This makes allocation and deallocation actually fast while aligning is only done at specific times and is done step by step so it does not stop the flow of the environment.
So where is the problem?
There are many calculations done like getting the end of the header or getting the byte after an allocation and doing addition and subtraction on them. I was good at math but its hard to focus that hard when you focus after 9PM and able to read the code I just wrote.
How will I solve this?
I will create some macros to simplify the calculations into macro calls. I am working on the macros (throughout the day) and hopefully I will retry to code on sunday night.
We are seeing progress and I am glad that its going well so far.
Wednesday, March 23, 2005
A bit of blogging
I bought myself a game two days ago for about 10$ (50 NIS in Israel) called 'Beyond Good & Evil'. And its been my latest thing from stopping me from focusing on Screens. Its so addictive that I spent playing it between 6PM-2AM last night without noticing the time fly by. I have decided not to by any more games untill Saturn is released.
About a release date... I realy cant say now... I will have more of a release date once I finish the core. So what is left currently in the core?
PrivateData - should of written it yesterday... see above why I didn't but I should code it today. CoreItem - Will code it next week and test it. Its a little complex but I should be able to do it.
CoreObject - This is where the fun begins since there is no more calculations but rather just structures and item allocations.
CoreFile - This deals with the 'stream' part of an object. You can read/write, resize and so on.
CoreNumber - This is a subset of CoreFile
CoreString - This is also a subset of CoreFile
CoreLink - This deals with the relationships of an object.
CoreFolder - This is a subset of CoreLink
CoreProperty - This is also a subset of CoreLink
CoreModule - This deals with module objects (like Applications and DLL's) which either hold code or point to code.
CoreMethod - This is also a subset of CoreLink
CoreTask - This deals with the task objects (like threads/proccesses)
CoreMessage - This deals with the queue that each task has
That is the Core. Most of the subsets are quite simple such as CoreString and CoreFolder. I will explain more on the components as I code them.
Sunday, March 20, 2005
A bit of history
Because I am deep into the internal sea of details, I get too carried away and show you all the technical details which are either not interesting (to those who have no idea what I am talking about) or just have no actual use. They are more usefull to me when I want to port Screens to other operating systems without hacking my head like I have done for the last three years. I haven't had a single day of screens without indulding my brain into it day in and day out.
Screens has changed alot over the years... who would believe that it was first created to be a common library so I could code some PalmOS games (still planned after Screens) and become a full-fledged multi platform environment designed to be a merging layer among operating systems to bring that unity to coding and user interfaces.
If you look at my development history you wont find anything... sounds a bit suspicious but then again I only got an internet connection when I worked for NDS (The company that creates the smart cards for DirectTV and other sattelite TV providers) in Jerusalem (Israel) in 1999. I just turned 16 when I finished a summer work for them so I was allowed legally to continue working for them. I worked on many internal projects for them and got alot of focus on MFC (Microsoft Foundation Classes) user interface development in Visual C++. I worked there for 3 years and it was basicly a walk in the park. I realy enjoyed my time there (mostly playing starcraft when fellow employees would pass by my office).
I only got my first home computer when I was 13 and was so amazed by it. Learnt Word Basic (for Word 7.0) and Visual Basic for Excel 7.0 and had my first environment where it was my solution to allow kids to have a customized user experience (with even a desktop background and per user settings) without ruining the computer for thier parents. I did alot of small projects for myself which sadly were lost with confronting the Chernobil virus twice (yep... 26th of april two years running because I replaced the computer but left the virus on the hard drive).
I would like to thank my father because not only did he get me interested in computers, he got me the summer job in NDS in the first place. Anyway...
So I was 17 or 18 (cant remember) when my girlfriend (now my wife, so far married for 7 months) gave me her Palm III device which she had no use for at all. I was absolutely amazed! I had noticed the Palm V devices in the stores but never bought my self one (although I could afford it then). It had 2MB of memory, small but expandable, pen based and fast... I enjoyed it for at least a year untill I found it dead from being sat on again and again in my jeans back pocket (where does it say not to put it in your back pocket in the instructions?). So my next device was the Visor Platinum with a Visor Phone. Walking around with that brick felt so good when people would stare at me. I loved being checked by security gaurds at the bus station to start having a convesation with them with 'what is that?' questions. My cat pushed the phone off a shelf and because I was basicly life dependent on it, I replaced it within a week with a Visor Pro. That lasted me untill I got a Tungsten E last spring when I got engaged with my wife and her father gave the handheld as a present (the ring was about the same price, so it felt even).
So where does Screens get in the picture? Just the spring before I left NDS I got inspired by a PalmOS application called 'Extended Window Demo' by Andrew S. Downs developed in 1999. It had movable windows which just sparked in me and thats how Screens started. It just continued from there, starting to add more and more ideas and the shedule just moved on and on. You can see most of the history still on 1src at http://www.1src.com/forums/showthread.php?t=5646
Carefull... its alot to read.
So thats basicly it... I have been working on Screens since... try to recode here and then (have rewritted just the few base components over 17 times) and redesign when I get stuck. Currently coding is going well and hopefully this will be the last rewrite untill the demo. I realy have a hunch on this version. The best way users can help me is to chat with me when they can via MSN Messenger or post comments on my blog or on 1src. The more questions the better it helps me fill the holes in my design and it allows me to get Screens out faster. For those who have sticked around since the beggining... THANKS. I know it must be hard to have faith with little substance but it will be fruitfull in the end and you will be graitfull for your support (I am already).
Friday, March 18, 2005
Heres another update
Hi Everyone,
Nope... the project is not dead, its still going forward.
So what has happened lately:
1. I have coded the PrivateRecord and PrivateDisk components... I have the PrivateData component to code this week and CoreItem component to code next week. I am late in schedule (I was meant to have a working demo by the end of march but then again I am never good at sticking to schedules).
2. The CoreItem component is now much better designed has a minimal footprint of only 4K without any items and items take only 128bits (16 bytes) per item. Objects are made of a few items so the overhead of each object is about 64 bytes. What does all this mean? It means that the more objects you have in the system there wont be much overload. The item component will get an editorial once its coded because its quite a piece of work. Each handle is fixed and is only 32bit and lasts untill the item is removed. It splits the 32bit into four 8bit indexes and in a tree design it finds the next address by each index untill the last index has the address of the actual data. This allows item blocks (which hold addresses of other items) to only be 1K and be movable without any problem. Only one location needs to be updated per item.
I will update you all next week once I finish the PrivateData component. I am very proud of my progress over the years and I hope to give you some kind of facts very soon (but then again... I am always late in my promises).
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