Wednesday, September 5, 2018

Stingray 1985 - 1987 series underrated

There is a movie from 2019 called Stingray, also known as Raymond, starring Joel Edgerton, Jon Bernthal and Anthony Hayes. I wonder if this is a sequel to the series by the same name which was originally aired in two seasons from 1985 to 1987 with a pilot of 90 minutes from 1984, featuring Canadian Actor Nick Mancuso, which I want to talk about.

I didn't watch it then. May be I thought it's another series with a talking car full of electronics. I thought of Knight Rider's K.I.T.T. Also Street Hawk, the series with an experimental super bike, came to my mind so I just ignored it.

Recently someone on Youtube showed a video composed of 1980s intros of shows loved by us teens then. Stingray was among them. I was instantly hooked by the musical score. Sounded to me like straight from Miami Vice and Jan Hammer on the keyboard. Instead it was done by Mike Post, Pete Carpenter, and Walter Murphy. Amazing!

I ordered a DVD set and enjoyed this short lived US series. "Ray", as he was called by others, is untouchable and almost always has full control of any situation. Even when it seemed he now takes some beating or was betrayed he will come out on top instead. Then he vanishes silently and without a trace like he appeared. He only revealed his real name once by whispering into the ear of somebody so the audience wouldn't know.

The series was well underrated. May be the move to the filming location in Vancouver in Canada, with its bad weather conditions in the second season and thus bad plots, led to the series cancellation. Too bad. If it would had stayed in sunny California it would had deserved a third season in my opinion.

Sunday, September 2, 2018

CP/M, the first operating system

The operating system CP/M

CP/M, the acronym for Control Program/Monitor or Microcomputer, is an operating system created in the year 1974 by Gary Kildall, founder of Digital Research. It is used on 8-bit Amstrad CPC and Amstrad PCW, Commodore 128, TRS-80, Osborne 1, BBC Micro, ZX Spectrum. It also found use on PCs, including the standard Amstrad PC-1512 in addition to MS-DOS and GEM.

For the Apple II, Microsoft created in 1980 the Z-80 Soft Card expansion card that allowed the use of the operating system of Digital Research. Early versions of MS-DOS were largely inspired, if not copied by CP/M.

Organization of memory

The memory of a computer under CP/M is divided into four parts:

  • BIOS: The Basic Input Output System for serial peripherals. It handles peripherals, floppy disks, monitor printers, etc. Usually, the BIOS occupies the "high" part of the memory.
  • BDOS: The basic disk operating system primitives. It contains the operating system. Usually, the BDOS is under the BIOS.
  • CCP (console command processor): Usually, the CCP is under the BDOS. This part of the CP/M corresponds to the user interface.
  • TPA (transient program area): This part of the memory starts at 100 (hexadecimal address). It is intended for user programs.

The different types of files

CP/M system stores files on floppy disks according to a specific logical organization, which has not been taken over by MS-DOS and can fill the disks. CP/M can also handle hard disks. In fact, as the BIOS is open, as clearly described in the documentation that Digital Research provided with some of its software, so it is possible to adapt any particular CP/M system to any available mass memory and devices available. Some computers running CP/M were originally sold with hard drives. Altos is one example.

Each file has a name and an extension.

  • ASM: assembler source file
  • PRN: assembler listing file
  • HEX: Machine language presented as a series of hexadecimal octets in Intel format
  • BAS: BASIC source file
  • INT: intermediate basic file
  • COM: command file, memory dump file, starting at address 100 hexadecimal under CP/M. Executable files always have the extension .COM
  • SUB: a file with a sequence of commands to be processed in batch mode by the command SUBMIT.
  • BAK: backup file is often used by word processing programs
  • $$$: temporary file, used for example by SUBMIT
  • LBR: archive file

Different orders of CP/M

CP/M commands can be internal or external, as was subsequently the case with MS-DOS. For the user under CP/M there is no difference between launching an internal command, such as DIR as *. * or an External like STAT as *. *. Or any other program.

Under CP/M, the shortest program needs only one byte, which returns to the System. On the other hand, it must be saved as an executable file using a .com extension, whose minimum size is one sector with a 128 bytes minimum.

The external commands of the CP/M or MP/M called programs of the same name which had the extension .COM or .PRL (only in the case of MP/M). Additional information: the MP/M was similar to CP/M but with a multi-user functionality.

Saturday, July 21, 2018

Gaps between primes

Everyone has probably learned in mathematics at school what primes are. They are numbers that are divisible only by 1 and themselves. So all the numbers that are divisible by 2 are missing.

Twin prime

While many primes are still close together for small numbers, separated by "even numbers", this becomes rarer as the number grows. For example, numbers less than 10 contain quite a few primes, so called twin primes which stand "side by side", separated only by even numbers. Like 2, 3, 5, and 7. The bigger the number, the less likely it is. For example, between 400 and 410, there are only the primes 401 and 409.

Cryptography uses primes to encrypt files and other data. For this large primes are used. Powerful computers are set to find ever larger primes, which turns out to be more and more difficult.

On the other hand, the question arises as to whether it is probable that, according to the currently largest prime number found, there are numbers that follow (after an even number) two prime numbers. Since there are an infinite number of numbers, I suspect that will eventually apply. Or maybe not? Nobody will have an answer for that until proven.

Or has any reader here an answer? Please comment.

Friday, June 22, 2018

Lucifer season 4

According to TV Line the series Lucifer was renewed for season 4, starring Tom Ellis, picked up by Netflix.

I liked the show. Wasn't my favorite show though but entertaining. But with season final of season 3 when Lucifer showed his devil face to Chloe Decker all the magic has gone. Because the show was all about others than God's children not knowing that Lucifer is indeed the devil. The show should in my opinion have ended there.

Then there were the two bonus episodes. Boo Normal which followed the timeline after his face was revealed but Chloe went on with business as usual, only briefly mentioning she saw much stranger things than what Ella reported to her. Okay, he is the devil, so what.... And Ella now revealed her personal ghost which actually also was an angel. I was afraid she would deal in about every future episode with that, making her a main character rather than a supporting cast member. While Once Upon a Time took place in an alternate timeline. This was rather boring and didn't fit well into a possible season 4 episode, especially after the cliffhanger with Lucifer revealing his devil face.

I wonder how they deal with these things in season 4. In my opinion they should have tied up loose ends and cancel the series for good after that.

Monday, June 11, 2018

The General Data Protection Regulation

Regulation No 2016/679, known as the General Data Protection Regulation (GDPR), is a regulation of the European Union which constitutes the reference text for the protection of data. personal data. It strengthens and unifies data protection for individuals in the European Union.

Development

After four years of legislative negotiations, this regulation was definitively adopted by the European Parliament on 14 April 2016. Its provisions are directly applicable in all 28 Member States of the European Union as of 25 May 2018. This regulation replaces the directive on the protection of personal data adopted in 1995 (Article 94 of the Regulation); contrary to the directives, the regulations do not imply that Member States adopt a transposition law to be applicable.

Main objectives

The main objectives of the RGPD are to increase both the protection of the persons concerned by the processing of their personal data and the accountability of those involved in this processing. These principles can be applied by increasing the power of the regulatory authorities.

Context

In January 2012, the European Commission proposed a comprehensive reform of the rules on the protection of personal data in the European Union. This reform has two components:

  • the updating and modernization of the principles set out in the 1995 European Data Protection Directive, in the form of this General Data Protection Regulation
  • the drafting of a new Directive on the protection of personal data in the context of police and judicial activities

The purpose of this new regulation is to give citizens control over their personal data, while simplifying the regulatory environment for businesses.

The European Parliament amended this regulation and adopted it on 12th of March 2014 at first reading. Negotiations continued between the delegations of the European Commission, the European Parliament and the Council of the European Union and ended on 15th of December 2015. The draft Regulation was passed in the Committee on Civil Liberties, Justice and Home Affairs. Home Affairs (LIBE) on 17th of December 2015. The European Regulation was published on 4th of May 2016 in the Official Journal of the European Union and enters into force on the twentieth day following that of its publication. This Regulation applicable from 25th of May 2018 is binding in its entirety and directly applicable in all Member States. The Facebook-Cambridge Analytica scandal, around the recovery and analysis of data for electoral purposes, bursts shortly before its implementation.

Wednesday, June 6, 2018

Zilog Z80 CPU

The Zilog Z80 is an 8-bit microprocessor designed and manufactured by Zilog. One of the peculiarities of this processor is the coupling of some 8-bit registers to a 16-bit register. This with a 16-bit address bus allows for much faster processing of data than with a conventional 8-bit processor.

This processor was marketed for the first time in July 1976. In the early 1980s it was very popular in the design of 8-bit computers such as Radio Shack TRS-80, Sinclair ZX80, ZX81, ZX Spectrum, MSX standard, Amstrad CPC, PC-88 and later in embedded systems. With the MOS 6502 family, it dominated the 8-bit micro computer market from the late 1970s to the mid-1980s and was still used in then new Amstrad computers until 1995.

The Z80 was designed to be compatible with the Intel 8080, so the majority of the code for 8080 could work without much modification on the Z80. The CP/M operating system was designed around Intel 8080 based systems and could also work without modification on Z80 based systems.Z80 based systems were generally more powerful and had more features than systems based on 8080 CPUs. Some versions of CP/M applications only existed in a Z80 version.

History and overview

Z80 CPU DIP by DamicatzThe Z80 came into being when Federico Faggin, after working on the 8080, left Intel at the end of 1974 to found Zilog together with Ralph Ungermann to put the Z80 on the market in July of 1976. It was designed to be binary compatible with the Intel 8080 so that most of the 8080 code, including the CP/M operating system, works without modification on it. The Z80 quickly took over share from the 8080 on the market, and became one of the most popular 8-bit processors. Perhaps one of the keys to Z80's success was the integrated refresh of DRAM, and other features that allowed systems to be built with fewer chips. For the first NMOS generation, the maximum clock rate increased gradually. First at 2.5 MHz, then by the well known 4 MHz (Z80a), up to 6 (Z80b) and 8 MHz (Z80h). A CMOS version was developed with frequency limits ranging from 4 MHz to 20 MHz and some versions were sold until the 2000s. The CMOS version also has a low power sleep mode, with processor state retention. The Z180 and eZ80, fully compatible derivatives, have specifications for up to  50 MHz.

Use in systems

The Z80 CPU saw uses including in Texas Instruments calculators, SEGA Master System, GameBoy, and Game Gear video game consoles. Some more powerful consoles with other central processors like the Neo Geo or the Mega Drive with its Motorola 68000, used the Z80 as an addon processor to handle sound or system I/O.

Saturday, May 19, 2018

The MOS 6502 CPU microprocessor

In the early '70s, a group of engineers from Motorola was convinced that it was possible to obtain a cheap microprocessor if a simple design and an improved manufacturing process were raised with respect to the standards of the time. Without the support of the company, this group would create one of the families of chips that would be the catalyst for the revolution of home computing, it is the 6502 and its successors, the main engine of the first Atari and Apple machines, between others.

Chuck Peddle was one of the leading engineers in the development of the Motorola 6800 processor, in his meetings with important industrial clients, he realized that the technology was appreciated, but too expensive to be used in a massive way. In conversations with his clients, he concluded that the cost of the processor had to go down from USD $ 300, which cost 6800 to only USD $ 25 at the time, a conclusion that did not make Motorola managers who had no motivation at all happy. to look to reduce the price of a technology that already had good sales.

Chuck Peddle and his work

For Chuck and other engineers it was an interesting technical challenge and without the support of Motorola they began to work on the necessary changes to improve their processor. On the one hand, the team was unhappy with Motorola's lack of support, and on the other hand the company was annoyed by Chuck's and his team's stubbornness, and finally the straw that broke the camel's back was Motorola's formal request to halt the project. that made Chuck and his team decide to leave the company, to continue working on their microprocessor on their own.

6502 CPU chip (C) commodore.ca

MOS

The group joined a low profile company called MOS, where they reached an agreement to participate in the profits that could be obtained with the new microprocessor, an agreement that from the MOS point of view was convenient due to the low profitability that meant in that time the production of these chips. This agreement, together with the mass resignation of Motorola was a demonstration of the confidence that the team of engineers had in the product they were developing.

The first processor of the 6500 series was 6501. An unprecedented fact that surrounded the development of this chip was that Chuck designed it completely by hand and it worked on the first attempt, when the normal thing in those years was to go through a process of over 10 failed attempts This processor was quite scarce since it was not made in order to be sold, but as a way to show Motorola how wrong they were, and that a useful and inexpensive microprocessor could be built.

One of the factors that influenced the reduction of production costs was an innovation of these engineers regarding the manufacturing process. In those times, the failure rate in production was 70%, that is, only 7 of every 10 processors manufactured went straight to the trash. This happened mainly because the process consisted of creating a large mold of the processor and applying reductions until reaching the real size, in these reductions errors always occurred and the engineers in MOS found a way to apply corrections to the mold in each reduction, achieving with this change a success rate of 70%, that is, 7 out of 10 processors were perfect.

The 6501, a Motorola clone?

The 6501 was fully compatible with the Motorola 6800 boards and could be used as a direct replacement at hardware level, which motivated a Motorola claim for alleged patent infringement of its former engineers. Supposed because in fact what was at stake was the intellectual property, since it was applying the knowledge of technologies that in fact were not patented. Even so an agreement was reached with Motorola and a sum of about USD $200,000 was paid to end the lawsuit.

The problem with Motorola caused the creation of the 6502, it was a 6501 but incompatible with the hardware designed for the Motorola 6800. The 6502 debuted at WestCon 1975 at the exact price of USD $ 25 that had been proposed. At first the attendees thought that it was some kind of scam, since it was not conceived to create such a cheap processor, but on the same day Motorola and Intel lowered the price of their 6800 and 8080 processors from USD $ 179 to only USD $ 69, validating the 6502 that was sold by the hundreds.

In the coming years Commodore, who was still in the calculator business, was going through financial difficulties as the business was going down and the competition was getting stronger. As a strategy to change the direction of the business, they bought from MOS, which was also struggling but had the technology they needed.

For Chuck Peddle the microprocessor business was geared to the industrial world, but while visiting different companies to try to sell the 6502 they told him that a couple of guys were trying to use their processor to build a personal computer. The fact seemed nice and agreed to go to help them to his garage, it was nothing more and nothing less than Steve Jobs and Steve Wozniak who worked on his first Apple computer. Chuck thought about introducing the 6502 into the industries and he did not suspect that a big market was in personal computers. Not in a million years! In his own words.

The 6502 is an 8-bit processor, which means that all its internal operations handle numbers between 0 and 255, on the other hand it has a 16-bit address bus that allows it to access up to 64KB of memory. The 6502 normally operated with a clock between 1 and 2 Mhz but given the same clock frequency it was capable of running much faster than the Motorola 6800, thanks to its clever design that reduced the number of clock cycles needed to execute an instruction .

Among the computers that were built around the 6502 are the Commodore PET, VIC-20, Apple I and II, BBC Micro and the entire line of Atari 8 bit computers such as the XL, XE, 400, 800, but also can be found in other types of devices, such as the Commodore 1541 disk drive for Commodore 8 bit computers. In the pioneering Atari 2600 console, an economical version of the 6502 known as 6507 was used, a version that had fewer pins and could only access 8KB of memory. The Commodore 64 also used a modified 6502, it was the 6510 where it added simple features that were usually implemented with additional circuitry.

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