* Posts by Richard Plinston

2608 publicly visible posts • joined 27 Apr 2009

The many derivatives of the CP/M operating system

Richard Plinston

Re: Yeah, no

> 1. The Apple II did not use variable-speed drives.

Yes, they did. https://collections.museumsvictoria.com.au/articles/1087

> hard sectoring was not because controllers were too slow to do soft sectoring.

https://en.wikipedia.org/wiki/Hard_sectoring :

"""Data read and write is faster in this technique than soft sectoring as no operations are to be performed regarding the starting and ending points of tracks."""

One is faster the other is slower!

Richard Plinston

Re: Origins

> Most commercial CP/M applications that were sold for MSX were re-written for compatibility and to take advantage of the much richer feature set. Borland's Turbo compilers come to mind.

Turbo-Pascal 3.x, for example, was produced in four versions: CP/M-80, CP/M-86, MS-DOS and PC-DOS. The first three had a configuration program which set the terminal type used. The MS-DOS version could be set to 'ANSI' and this would work on an IBM-PC or close that had ANSI-SYS configured in CONFIG.SYS. But other terminals could be configured for non-IBM-PC machines (DEC Rainbow) or those using serial terminals (Wyse 60, DEC VT52, etc). The CP/M-xx versions had dozens of terminal types to select from.

MSX-DOS 1.x could run the standard CP/M-80 version without a 'rewrite'. It did need to be on an MSX-DOS disk though. It seems that it was rather limited and could only use console mode (ie scrolling text) because MSX-DOS did not support ANSI.SYS. Certain libraries, such as Popolony2k, were available that used INLINE assembler code to access MSX facilities.

Richard Plinston

Re: Origins

> MSX-DOS was in no way based on CP/M and provided effectively a clone of MS-DOS

What you say is nonsense because MS-DOS itself is 'based on CP/M' design (if not on source code) because it implements the same BIOS/BDOS/CCP structure and it implements the same CP/M API with only minor variations. It even supports the same 'page zero' structure (in the PCB on MS-DOS) including the FCBs and the 'call 05H' interface. MS-DOS 1 could only run .COM '8080 mode' programs which were structurally identical to CP/M .COM programs.

While MSX-DOS was not 100% compatible to CP/M it could not run MS-DOS programs at all, not even .COMs.

> CP/M compatibility was at best an afterthought

No.Wrong. CP/M compatibility was the _whole_ point of MSX-DOS (and of MS-DOS 1.x). Without it there would have been _no_ application programs that would run on it, at least in the first several months, and no point for anyone to buy the system.

Richard Plinston

Re: Yeah, no

> CP/M floppy formats were vendor specific

CP/M came out when 5.1/4 disk drives were very new and the electronics for drive controllers were slow and expensive. This meant that 'tricks' had to be used to get the best performance for the least cost.

Some used variable speed drives (eg Apple II), some used hard sectored disks with 10 index holes (eg North Star) because the controllers could not keep adequate timing from a single index per revolution. Most could not read or write sequential blocks, they were to slow to be ready so if the blocks were sequentially numbered around the track it would take 8 revolutions to read a complete track. By interlacing and numbering as, say, 1,4,7,2,5,8,3,6 it would only take 3 revolutions. All these were vendor specific.

By the time the IBM-PC and MS/PC-DOS came out 7 years later the controller electronics were much more capable and these tricks were no longer required.

Richard Plinston

Re: Yeah, no

> The only improvement MS-DOS made over CP/M was a single disk format.

The IBM PC originally had 5.1/4 160Kb disks, 320Kb double sided, then 180Kb 9 sector and 360Kb double sided. The IBM PC Jnr had 3.5inch 720Kb while the AT had 1.44Kb.

While PC clones followed the IBM formats. other manufacturers made MS-DOS machines that were not clones and they had a variety of different formats. There were utiliiites that could read these various different formats, just as there were for CP/M, granted there were much fewer for MS-DOS.

With hard drives MS kept the 32Mbyte paritition limit well past its 'use by' date and this led to various PC manufacturers (Compaq, Wyse, etc) and drive makers changing their versions amd/or drivers to support larger disks in incompatible ways. It was IBM that eventually rewrote the code into PC-DOS 4 and passed this back to MS to make 4.01* that finally made compatible hard disks with >32Mbyte partitions.

* not to be confused with MS-DOS 4.0 and 4.1 which were [sort of] multi-tasking versions also referred to as 'European DOS' because they were used by Siemens and ICL as well as Wang.

Richard Plinston

Re: Yeah, no

> So, yes, DR-DOS is 100% a derivative of CP/M.

It is actually completely irrelevant what you consider to be 'derivatives' for the purposes of this license. The only relevant usage is what DRDOS Inc thinks is "CP/M and its derivatives' and that semms to be entirely CP/M itself plus, probably, CP/M-68K and CP/M-Z8000.

Richard Plinston

Re: Was CP/M an operating system?

> [0] "PC" defined as a machine designed to be used by a single person,

The first computer that I 'used' was a small mainframe ICL 1901. I often ran it alone, changing the tapes and disks, loading the paper in the printer, the cards in the reader and starting the programs. You seem to calling this a "PC".

The first computer to be _called_ a 'personal computer' was the Apple II in adverts in 1978.

Richard Plinston

Re: Was CP/M an operating system?

> No, CP/M wasn't an OS. It was a glorified program loader.

It never claimed to be an 'OS', it was a Control Program, that is what 'CP' stood for. It was, however, a subset of an OS, a DOS: Disk Operating System, providing that functionality without the other parts that would make it a full 'OS'.

> And (IMO) MP/M.

MP/M provided many more facilities including multi-tasking, multi-user, bank switching ,networking (DR-NET), RAM disks, and, no, programs could not 'take control' of all the hardware.

Richard Plinston

Re: My first personal computer os

> My last cpm experience was Dr dos,

An interesting comment because DR-DOS could not run CP/M software

> they could network well before dos or windows could.

MP/M was originally developed in 1978 to be a network server for CP/M workstations using DR-NET. As it was also a multi-user system that could be used with relatively cheaper serial terminals it found its niche there.

Richard Plinston

Re: Yeah, no

> And it was Xenix in name only

Microsoft had licenced the use of Unix source code in 1978 but did not have a licence to use the name UNIX so it called it XENIX. Yes, that was its name. MS announced the product in August 1980.

> Everybody (nearly!) used existing source code as a reference and framework

Microsoft was very protective of its source code. While many were implementing some form of BASIC, usually incompatible, they were not doing so by using MS source code. The implementations of MS-BASIC on many different machines was done by MS themselves or under strict licence conditions. Even DRI had its 'Personnal BASIC' which owed nothing to MS source.

You should note that Bill gate's letter was complaining about the distribution of the binary loadable BASIC interpreter (initially on paper tape) and not of the source code which was only ever on DEC machines where it was cross-compiled to the target machine.

Richard Plinston

Re: Yeah, no

> Just as MS did later with AT&T Version 7 UNIX, which MS distributed as Xenix ...

Actually, MS Xenix predated 86-DOS/MS-DOS by a couple of years and wasn't 'later'.

> and everybody+dog did porting BASIC to all and sundry.

'Porting' usually refers to using a particular set of source code and modifying it to run it on a different OS or machine. The BASIC language was originally developed by Kemeny and Kurtz in 1964. Many somewhat different languages were later developed and called BASIC even if they were fundamentally differernt from K&K's. While MS did *port* their MS-BASIC to many different machines, including the Apple II (in conjunction with Applesoft) i doubt that company could be called 'everybody+dog".

The word you were grasping for is probably 'implementing'.

Richard Plinston

Re: Yeah, no, yeah

> The FAT's borrowed from M$ Disk BASIC were very different from CP/M's file handling.

Yes it was and it was very slow on large random accessed files. I developed COBOL applications for business that could run on DRX (DRS20), MP/M, Concuurent-xxx. These used ISAM files for their data. When ported to MS-DOS they ran really slow compared to the DRI based systems. The problem was traced to the FAT index. Every random access had to start at the first block of the file and track down the FAT table to get to the data block requested. Using DR-DOS to format the disk allowed me to increase the cluster size to 8K while MS-DOS FORMAT only formatted to 2K clusters. This reduced the FAT table access by 4 times and gave an overall performance increase of 3 times.

The CP/M based file systems were archaic but accessing randomly gave a reasonable performance because each directory entry had a larger range of blocks and thus fewer disk accesses.

Unix/Linux INode systems are much better at random access to files than either of those above.

Richard Plinston

Re: Yeah, no, yeah

> COMMAND.COM had a lot more internal commands (e.g. COPY, ERASE, support for .BAT files) than the CP/M's command interpreter.

Yes, on an 8086/8088 there was usually much more RAM than on a 64Kb (or less) 8080/Z80 machine so utility code could be incorporated in a larger CCP. CP/M did have a SUBMIT utility though.

> 86-DOS did not freeze when attempting to read/write from an open floppy disk drive.

No, it crashed the program!! On CP/M the BDOS checked that the _correct_ disk was inserted. MS-DOS (at least until 3.1) did not check, if a disk with open files was swapped then MS-DOS would happily overwrite this new disk and corrupt it.

Richard Plinston

Re: Origins

> and a compatible OS on MSX machines, mainly in Japan.

MSX-DOS was a Microsoft product that provided an emulation of CP/M on Z80 based MSX machines.

Richard Plinston

Re: Yeah, no

> contemporary person remains a descendant.

But an adopted child isn't. Completely new code is not a descendant of previous code (no derived DNA) even if some of the functionality is re-implemented.

Richard Plinston

Re: Yeah, no

> Concurrent CP/M was CP/M-86 merged with MP/M-86.

This is just dogma. Concurrent-CP/M did not need to be 'merged' with CP/M-86, it was MP/M-86 with added multiple virtual screens replacing MP/M's screen switching code. That is MP/M, MP/M II, MP/M-86 could switch terminal sessions using Ctrl-D. This would hibernate the current program and switch to a different session. Concurrent-CP/M could maintain several sessions per screen without having to hibernate the programs that were in background.

Richard Plinston

Re: Yeah, no

> Both CP/M-86 and MP/M are derivatives of CP/M.

There may well be a case for saying that CP/M-86 is a derivative of CP/M in that the structure of the code of the BDOS and the CCP are much the same and could be regarded as a code enhancement and/or conversion from the original.

MP/M was completely new code. the base code in the system was the interrupt system and the 256 queues. It also had bank switching. The BDOS in CP/M was simplistic and used a single 'thread'. That is once a request was made it ran without interruption until the request was completed. In MP/M and all later multi-xx DRI systems a request was queued and return was made to the system. On appropriate hardware this resulted in the CPU being used for other tasks while the disk was moving the tracks, waiting for rotation and transferring the blocks. At the end of this it signalled that the request was completed and the requesting task was put back on the queue to to scheduled at the next interrupt.

i don't know what you count as 'derivatives'. Certainly all DRI systems had a CP/M-like API, but so did MS-DOS and clones of which there were many. There are even emulators that run CP/M programs on Unix/Linux or Windows.

> DR-DOS inherits from the native x86 version of CP/M which was ported from the 8080.

NO. DR-DOS (and DOS-Plus) derived from Concurrent-DOS, NOTt from CP/M-86. In the original versions it used the same source code tree which was completely separate from CP/M-86.

I have several CONUG newsletters with articles, some written by Gary, that explain this.

Richard Plinston

Re: Yeah, no

> Pascal-like high-level language

PL/M is not particularly 'Pascal like'. It is mainly a subset of PL/I and has similarities to Algol, C and other high-level languages.

Richard Plinston

Re: Yeah, no

> based on the same code,

While CP/M-86 may well be based on some of the same PL/M code for the BDOS, with modifications to handle the segmentation required by the 8086, MP/M, MP/M II, and the various Concurrent-xxx and further derivatives of those were complete rewrites with no common code.

The BIOSes were also completely different code, some of the utilities may have been retained.

Even DR-DOS was a derivative of Concurrent-DOS (with multi-tasking/user removed) and was _not_ a derivative of CP/M-86 with FAT and .EXE support added.

Richard Plinston

Re: Was CP/M an operating system?

> creating Unix in 1969!!!.

UNIX was originally created as a UNI (single) version of MULTICS. Most of its features, such as the INode file system, were based on that GE system. Multi-user was added later.

Richard Plinston

Re: Was CP/M an operating system?

CP/M was a DOS - a Disk Operating System -- it provided the facilities for programs to operate on disks. Other systems may also have provided multi-tasking and multi-user (such as MP/M), or graphics 9such as GEM).

Richard Plinston

Re: Paul Allen

> MS threw together its seat-of-the-pants OS for the Altair

You are very generous in calling it an 'OS'. The stuff written for the Altair was just a BASIC interpreter* and it was loaded into the machine using paper tape created on a DEC machine.

* It is also alleged that the core of the BASIC interpreter was created from an open source BASIC available on DEC machines and used by Bill Gates at Harvard. The math routines needed a complete rewrite for the 8080 written by Monte Davidoff.

Richard Plinston

Re: Yeah, no

> even the bugs were the same to begin with

Exactly. The particular bug that identified it as being 'copied' from CP/M 1.3 was a particular corruption of an FCB (File Control Block and yes, MS-DOS did use these) in specific circumstances.

Richard Plinston

Re: Yeah, no

> DR-DOS 100% *was* a derivative, yes.

DR-DOS was not a derivative of CP/M, it was a derivative of Concurrent-DOS with (most of) the multi-tasking and multi-user stripped out. C-DOS was a derivative of MP/M-2 via Concurrent-CP/M. MP/M was a completely different set of code from CP/M.

I used (and programmed for) DR-DOS since version 3.0. DRI DOS-Plus (which I have on a BBC Master 512) was also a derivative of Concurrent-DOS and retained some of the multi-tasking. One of the features of DR-DOS was that it would run in ROM because the code segments were 'pure'

Richard Plinston

Re: Yeah, no, yeah

> DOS was not a derivative of CP/M

CP/M was developed on DEC machines when Gary was contracted to work for Intel to write a PL/M compiler that ran on DEC to produce 8080 code, so of course it looked like other DEC software.

QDOS (Quick and Dirty OS) was Patterson's original port of CP/M to the 8086 in order to develop an OS for the 8086 version of the SCP Zebra. SCP were full DRI OEM licence hoders with all the CP/M source code that DRI would release (as were Microsoft for the Z80 Softcard that was their major revenue in 1980). The CP/M BDOS was written in PL/M and DRI did not release the source code for that but there were 'annotated decompilers' available for CP/M 1.3 that produced 8080 assembler code from the binary. There was also an 8080 to 8086 translator provided by Intel that would convert the assembler code. It is alleged that this is how QDOS was originally developed. It was brought up on a 8086 Zebra initially by creating a CP/M disk with the QDOS OS on it and then switching processor borads and booting QDOS, thus this did have the CP/M disk format. Later Microsoft provided the FAT disk system from 'Stand-Alone BASIC and this was incorporated to create 86-DOS (otherwise known as SCP-DOS) which was licenced to ibm and MS.

It is alleged that Gary Kildall was able to bring up a DRI copyright message on a PC-DOS 1.0 system and IBM settled with DRI by agreeing to sell CP/M-86 alongside PC-DOS (but never updated from 1.0), gave him money, and rewrote the BDOS to create PC-DOS 1.1 and MS-DOS 1.25.

Richard Plinston

Re: Concurrent CP/M and ICL 80286 hardware

MicroLAN was 1.25 Mbit/sec. It originated on Cogar desktop machines in 1976. Cogar was bought by Singer Business Machines and then ICL bought part of SBM. ICL produced the Cogar machines as ICL 1500 series (not to be confused with the ICT 1500s). The replacement machines were the ICL DRS20 series which still used 1.25Mbit/sec MicroLAN to connect servers and workstations.

I worked on DRS20, including a prototype, using Retained mode (1500 emulation) and Native mode 8085AH2.

The ICL PC2 (8085 and 8086), Quattro (8086) and Quattro-XM (80286 plus bank switching) were desktop machines with serial terminals running MP/M-2, Concurrent-CP/M, Concurrent-DOS or Concurrent-DOS-XM as appropriate. There was a network system available to connect these computers together using DR-NET software over a token ring by connecting to the synchronous port of the machine. I still have one of the adaptors here. It wasn't MicroLAN though.

An enhanced version of MicroLAN was used to connect DRS303 and DRS305 terminals to DRS300 computers or link computers together. It was still 1.25Mbit.sec.

i still have some of this kit laying around here, a ton or two of it was thrown out a year or so ago.

An open-source COBOL contender emerges

Richard Plinston

Re: Scary

> business process, ... that might date back decades

The thing about business processes is that they change frequently. Businesses are about competing with others and trying to increase their revenue and profit. They will change the way they set prices, discounts, they will change the product they sell, the way that they sell them. If they don't do that then their competitors will and will take business from them. The computer systems are required to be amended to implement these changes.

> rewriting the code in a modern language

Back in the 80s there was a Datamation survey that reported that 80% 9or so) of COBOL programming was reported as being 'maintenance' whereas 90% of C programming was new applications. Some seemed to conclude that if COBOL programs were converted to C then the 'maintenance overhead' would disappear and the programmers would create new applications.

The whole survey was seriously flawed. The COBOL and C sites were doing completely different types of applications. The COBOL 'maintenance' was, in fact, updating the business applications to handle changes in the business processes as the businesses re-invented themselves to compete better.

What's the top programming language? It's not JavaScript but Python, says IEEE survey

Richard Plinston

> Is Python a ...

Yes, all of those, and an embedded language too, if you want that.

Richard Plinston

Re: What about people just using the language, and not talking about it?

> none doing the auto-complete and code navigation

Try PyCharm. There is a community edition.

Richard Plinston

> it has a too-rapidly-changing standard.

2 in 30 years?

Actually it is quite easy to write code that runs perfectly with both Python 2 and Python 3 using the futures module.

Richard Plinston

Re: Misunderstood purpose

> niche languages, all promising to eliminate logic and construct errors by design

I initially read this as:

niche languages, all promising to (eliminate logic) and (construct errors) by design

But I suspect that this should be read as:

niche languages, all promising to eliminate (logic and construct errors) by design

Richard Plinston

Survey basis

> Or which have most job opportunities?

That would seem to favour languages for which there are the most empty desks. The reason they are not filled may be that few want to use that language.

> how much code is written in each language?

That would favour verbose languages (COBOL, Java) where everything has to be re-invented for every project. Or, possibly, where developer productivity is measured by number of lines of code written per day.

> Google Search and/or tutorials

That would relate popularity of a language to the number of people who don't know it.

It seems to me that Javascript is high on every list because it it hard to avoid when doing web development even when any other language would be preferred.

Get ready to make processes fit the software when shifting to SAP's cloud, users told

Richard Plinston

> the way you've operated a certain business process five years ago is not the way you want to operate it today,

I spent 50 years developing and changing bespoke software for several clients. Businesses are deliberately different in order to be competitive against other businesses in the same market. Not only do they want to be different from others in the market, they want to be different than what they were last year.

The business environment changes: eg banks no longer take cheques, the processes need to adjust, the software needs to follow the processes, or indeed, enforce the changes that have been determined by the management.

On the other hand the business will often operate in spite of the laid down procedures.

Microsoft suspends free trials for Windows 365 after a day due to 'significant demand'

Richard Plinston

Re: How much?

> An eight core system for $158 a month?

You have forgotten to add in the client machine cost and the cost of upgrading your bandwidth.

Microsoft wasn't joking about the Dev Channel not enforcing hardware checks: Windows 11 pops up on Pi, mobile phone

Richard Plinston

Re: Windows Mobile holdouts, still mourning the death of their beloved operating system

> it's the only MS OS that MS killed off.

Windows RT?

Developing for Windows 11: Like developing for Windows 10, but with rounded corners?

Richard Plinston

Re: Linux is a desktop OS

> But then, under that (mistaken) belief, so is Unix.

Of course it is. Mac is BSD (Unix) based and it is a great desktop system.

> Taking a server OS and topping it with a window server makes it 'desktop"

Windows NT was developed as a server OS, the original design included it being multi-user*. Windows NT 3.1 had a GUI, basically from Windows 3.1, added on top. The NT design still underlies all the subsequent versions of Window.

> Linux kernel is multiuser server. If [we] press it into single-user desktop use

Unix, Linux and Windows (post 3.11) are all pre-emptive multi-tasking kernels. The only difference in being multi-user is that the user id is attached to the process and this is checked against the various security settings and attributes. As Windows does this too then it is actually a multi-user kernel, it is just not simultaneously multi-user (except TSE and/or Citrix). It can swap users and may even be able to leave the original user with some idle processes until they swap back.

* the multi-user bit was removed because Bill wanted to sell a copy to every user rather than one copy for a bunch of users. This was added back for TSE.

Richard Plinston

Re: New here

> Desktop OS's have a fundamentally different paradigm than a server OS,

So, you are saying that Windows Server is crap!

> Windows, is criticized for just about *everything* ... [rant on] ...

Yeah, people want choice. One size does _not_ 'fit all'. Get over it.

What you need to know about Microsoft Windows 11: It will run Android apps

Richard Plinston

Re: Linux Subsystem - Android?

> Android apps are effectively Java apps.

While many Android apps have been written using the Java language, they are actually Dalvik apps that run using the Dalvik VM or ART. They do not run on any Java VM.

Stop. Look... Install Linux? The Reg solves Microsoft's latest Windows teaser

Richard Plinston

Re: A slight to Tim Berners-Lee

> To say the web was born and grew up on Windows is an outright falsehood

Not only that but Windows 95 initially attempted to replace the internet with Microsoft's own network, the original MSN. To access the internet one needed to buy the Plus pack or use 3rd party software. Later releases did include internet access because MSN failed.

The quest for faster Python: Pyston returns to open source, Facebook releases Cinder, or should devs just use PyPy?

Richard Plinston

Re: C and then some

> If you absolutely, positively need performance above all else, then there aren't really many useful alternatives to C

Several years ago I wrote a program in C that merged data into a postscript template, eventually to produce PDFs for such things as invoices and statements. Later, I rewrote it in Python and it ran several times _faster_ than the original.

The reason that the C code was slow was that it used the std library string functions. All the data merging was done using strfind and strcat and these keep scanning along the string to find the null terminator. Python keeps the string length in its object and thus has much faster string handling.

Microsoft loves Linux – as in, it loves Linux users running Linux desktop apps on Windows PCs

Richard Plinston

> fragmentation of desktops and distributions

Windows XP, Windows Vista, Windows Mobile 6, Windows 7, Windows Phone 7, Windows 8, Windows RT, Windows Phone 8, Windows IOT 8, Windows 10, Windows Mobile 10, Windows 10S, Windows IOT 10, Windows 10 ARM, ...

Richard Plinston

Re: @Boris the Cockroach - They

> Linux dead or alive no longer matters for Microsoft.

It obviously _does_ matter to Microsoft, if it didn't they would ignore it. In fact it matters because many cloud customers run Linux workloads.

> Pay for a Windows license, sign in with your Microsoft account and you're free to run Linux.

Or: don't pay for for a Windows license, don't have a Microsoft account and you've always been free to use Linux.

I am not sure why you think that Linux users will replace their systems with Windows running Linux apps. How many Windows users replaced their Windows systems with OS/2 systems because OS/2 could run Windows apps?

In fact quite the opposite happened. Instead of there being OS/2 versions of apps, developers just made Windows versions that would run on Windows and OS/2. Now developers can just make Linux apps that will run on Linux or Windows.

Richard Plinston

Re: Yes, of course

> KDE has been available for Windows for years

So has GTK, the graphical basis of GNOME. Back in the 90s I developed GUI applicationa using Glade* and Python that ran on Linux and Windows with zero code changes, not even a recompile. It even ran on Nokia 800 with a few minor features missing.

* Glade is a graphical interface designer for GTK projects.

Richard Plinston

Re: Yes, of course

Around 1990 I was asked to develop a graphics system to augment an existing text based system. It was for loading container ships and would have graphics representation of the ship and each bay and the containers and of the various tanks. It would have bending and shear graphs, stability, hazardous separations, and much more. It wasn't just GUI dialogs, it was full graphical, it eventually even had a 'helm view' as if looking forward from the helm (or indeed any chosen point) to ensure that the loading and trim met visual sighting requirements.

At the time I was running multiuser systems with Windows 3.1 hosted and an OS/2 system. I had compilers that would produce code for Windows 3.1 and for OS/2 and so I could make a choice whether to do the graphics in Windows or Presentation Manager.

When OS/2 was released with a Windows 3.1 sub-system the choice was obvious.

Penguin takeover: We tried running some GUI Linux apps on Windows the official way – and nothing exploded

Richard Plinston

Re: Why?

> Why? would a GNU/Linux developer want to develop any GNU/Linux code on MS Windows anyway?

They don't, but MS wants to force corporates to make these developers use Windows. Clouid users run Linux VMs and developers write Linux programs to run in those VMs. MS wants those developers to use Windows to ensure 100% Windows usage in corporate sites.

Perhaps there will be some tweaks in Azure so that the Linux VMs will only run programs developed with WSL.

Richard Plinston

Re: Comparisons please? Benefits please?

> Why would you develop Linux code (NOT apps, PROGRAMS) on Windows to be deployed on Linux?

Because cloud customers use Linux VMs. "about 50 percent of all Azure compute cores are Linux."

MS wants those developers to use Windows.

IBM creates a COBOL compiler – for Linux on x86

Richard Plinston

Re: [Aside] Storage media

> But I was using an ICL mini computer, not IBM, and I'm sure the floppy discs were 9".

No, they weren't.

ICL ME29 had 8 inch discs.

ICL DRS20 Models 40 and 50 had 8 inch.

I still have some 8 inch discs that were used in those systems.

Chill out, lockdown ain't over yet – perhaps FUZIX on the Pi Pico could feature in your weekend shed projects

Richard Plinston

Re: Young people these days...

> 32kb of RAM

Anything with only 32Kb of RAM would be only an 8bit CPU (8080, Z80, 6502) and Linux never ran on those.

Richard Plinston

Re: Young people these days...

> Toshiba notebook which has 32kb of RAM

Most likely it had 32Kb of _Video_ RAM. This number would be displayed when booting. To run any minimal version of Linux would require at least a megabyte, probably 2 or 4 of actual RAM.

Maybe you ran Minix but this required 640Kb.

Happy birthday, Python, you're 30 years old this week: Easy to learn, and the right tool at the right time

Richard Plinston

> it's now Python3 only

To install Python 2 version on Ubuntu 20.04 open a terminal and enter one of the following commands:

$ sudo apt install python2


$ sudo apt install python-minimal