Monday, March 31, 2008

Homebrew Apple II+ Diagnostic Tool

Rummaging around in a stuffed drawer one day I came across a computing project from the past for an Apple II+...

My first personal computer was a built from a kit, the Heathkit H-8. That one was based on an 8080A CPU, 4KB of static RAM and a front panel monitor based in octal. Well, after the solder smoke cleared there was a fully functional computer in front of me with a cassette player to load and save data. Programs were created with either a BASIC interpreter or a far less used FOCAL language and even less via the front panel I/O capability.
Later I obtained a breadboard and with some BASIC peeks and pokes was able to actually have the terminal inform me that lights were either on of off in the room. The future was finally here!

A couple of years later I purchased an Apple II+ with 16KB of dynamic RAM, later upgraded to 64KB. This was of course a much more useful PC application and program learning wise than the H-8 mainly due to the variety of applications available as well as UCSD Pascal.
I subscribed to magazines both Apple specific and computing in general. In one of these magazines an article described a home brew project along a schematic to build a diagnostic device to examine the address and data states on an Apple II+ bus.

This diagnostic board had 16 red leds representing the address bus and 8 red leds representing the data bus. The led being lit indicating a binary 1 and a binary 0 for an unlit led. In the upper left there were 3 green leds which represented the Ready, Write, and Sync CPU indicators for the 6502 CPU.

There were 3 control switches in the upper right. The first being a toggle switch which would place the CPU in either Halt or Run mode.
The second 2 switches were momentary switches with one being to execute a Single CPU Cycle and the other to execute a single CPU Instruction.

The card was made with IC sockets and wire-wrapped on the backside. The logic consisted of the 7400 variety of integrated circuits which ranged from de-bouncing the mechanical switches to driving the leds through current limiting resistors. The usual +5VDC noise eliminating capacitors were wired across various points in the power supply runs.

Below is a close up of the LS373 tristate latches which were the direct interface to the address and data bus signals. The '1's and '0's on the bus were latched onto and displayed on the led indicators depending on the directives of the switches.

Although it was actually never used to diagnose a problem it was a good learning tool, especially when used with ORCA/M (Object Relocatable Code Assembler for Microcomputers), which was a very nice code assembler for the 6502 CPU and Apple.

Note that time takes a toll, a 9 volt battery was used to illuminate the leds for the purpose of these images.

Friday, March 28, 2008

Observations on wars

There are many definitions of war and causes for a war. No matter the source for an exact definition, or a definition that one accepts it can generally be understood that war is a condition of human existence that is best avoided.

The wars briefly discussed in this blog shall be limited to wars that began and continue to occur in my lifetime. These wars have many traits in common as well. Most had their genesis prior to the birth of most of the people reading this. Many if not most started with a well intentioned government to improve the quality of American Life during the industrial revolution and the population increases of the early 20th century.

What happened along the way?

  • The Pure Food and Drug Act of 1906 was a well intentioned act that provided clearly labeled drugs and food and other products in this time when products were undergoing more durable packaging and transport to further reaches of the country - as well as keeping dubious sellers from selling inferior and counterfeit or tainted products.
  • The Harrison Narcotic Tax Act 1914 a form of control of opium and coca in their various forms and thus possibly provided the beginning of legislative control of what Physicians could provide for their patients.
  • Prohibition of Alcohol 1920-1933 Much of this drive came from religious ideology (temperance).
  • Marijuana Tax Act of 1937 Maybe the most recognizable Act of the 1930's
The sum of these and many more historical steps led President Nixon to officially use the term War On Drugs in 1972.

Another noble idea that most people would agree on would be to eliminate poverty. So, in the State Of The Union Address given by President Johnson on January 8th 1964, he was to declare a War On Poverty.

As legislative evolution does, these ideas, laws, enforcers and the forces of warriors refine and get tougher when wars are not won in a reasonable amount of time. Soon more agencies are established, think tanks and religion adopt the cause and Praise The Lord And Pass The Ammunition songs are written. Although from a different kind of war this was an actual song from World War II.

When the word war has such a negative connotation one wonders why there cannot be other words to use for these ideas - after all it is the American People and lots of collateral damage and national treasure has not reversed the trend.

How has the War On Drugs gone? Any end in sight?
How has the War On Poverty gone? Any end in sight?
How will the War On Terror go? 100 years?

The war on terror has been with us for some time now and what would be one's next guess as to a war on something?

As an aside, all of the wars mentioned here seem to occur in nations other than America in the same time frame - not always, but enough that it seems odd.

Thursday, March 27, 2008

POTUS 2009 - Where is our salvation?


Hillary dodges bullets in Bosnia and will 'provide' everyone with health care (business as usual)

McCain will follow Bin Laden to the Gates of Hell and save America (business as usual)

Obama will heal and bring America together (business as usual)

A Patriot SOBS at the ( Same Old Bull Shit )


America needs a group of people that stand for what the Founding Fathers created. So that we may have an American Class that stands above 'World Class'. The below video is 65 minutes long but if one is serious about the future of this country -please give it a view.

If you don't have the time - just read about Ron Paul here.

Why does it have to do a damn fsck ?!?!?

In the very large Unix computing company I worked for some years ago there was this power failure that lasted maybe 30 minutes or so one afternoon...

If you have worked in the computing industry you no doubt have run across this type. A middle aged balding, maybe just a bit cross-eyed person that makes more than you do. This is the guy that is more than slightly odoriferous with perpetual microwave popcorn oil on his hands holding a 32 ounce plastic cup which he just filled up from the community coffeepot.

In his office the bookshelf is lined with many books in pristine condition, purchased on the company dime of course. In this case I would have bet that every Java book that was published at the time by O'Reilly was present and accounted for on his bookshelf. It was pretty to see them all lined up so neat and graceful on that shelf. The microwave popcorn oil never made it to the books.

At times this person had anger management issues no doubt caused by the economic turmoil and downfall of stock option value of which he no doubt had a vast fortune.

So the storm passed that afternoon and the power was returned and people started trudging back to their offices to get back to their tasks. This developer turned on his workstation, turned red with an angry look on his face and uttered "Why can't they make it so it doesn't have to do a a damn fsck!!!"

Just to put the proper perspective on this true tale - he was a developer in the network storage group.