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Hello World on z/OS

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Re: Hello World on z/OS

#91

Post by southern_cross »

Xarodon wrote: post #44
jareds wrote: post #19

Earlier quoted context omitted.

I've been working on Mainframes for the passed 8 years full time, and several internships before that. I often go several days with out needing to use ISPF. I use https://compuware.com/workbench-mainframe-modernization/ for dataset editing, job submission, etc. I find the Unix shell you access through ISPF to be very difficult to use. Luckily SSH is available on z/OS, so if I need to do Unix stuff I can just SSH in w…

> The issue I still have with the Mainframe is documentation. Unlike most programming questions a google search does not turn up Stackoverflow results. I find I spend a lot of time going through random forums or reading the IBM doc. I don't find IBM doc easy to understand, but the more I have to deal with it the easier it gets. You're not alone my friend, those IBM docs certainly are not easy to read/understand.

> You're not alone my friend, those IBM docs certainly are not easy to read/understand.

Just as for Unix, Linux, Windows, and so on, there's an IBM "culture" (terminology, conventions, etc.) that you have to get used to. (It often helps to know some of its history, too.) But since I grew up professionally with one foot in the IBM world I usually don't have much trouble at all reading their docs.

Re: Hello World on z/OS

#92

Post by southern_cross »

jareds wrote: post #19
sien wrote: post #10

Earlier quoted context omitted.

They and others have. There are ways to develop in Eclipse that can target z/OS. https://developer.ibm.com/zsystems/documentation/java/jzos/j... https://www.ikanalm.com/solutions/devops-and-toolchain-orche... However, the people who develop for z/OS are often people who are familiar with Interactive System Productivity Facility (ISPF). It's a bit like whether people who are proficient in Vim or Emacs really benefit t…

I've been working on Mainframes for the passed 8 years full time, and several internships before that. I often go several days with out needing to use ISPF. I use https://compuware.com/workbench-mainframe-modernization/ for dataset editing, job submission, etc. I find the Unix shell you access through ISPF to be very difficult to use. Luckily SSH is available on z/OS, so if I need to do Unix stuff I can just SSH in w…

FYI, https://www.reddit.com/r/mainframe is a thing, as is http://terminaltalk.net .

Re: Hello World on z/OS

#93

Post by southern_cross »

krylon wrote: post #45
jareds wrote: post #19

Earlier quoted context omitted.

I've been working on Mainframes for the passed 8 years full time, and several internships before that. I often go several days with out needing to use ISPF. I use https://compuware.com/workbench-mainframe-modernization/ for dataset editing, job submission, etc. I find the Unix shell you access through ISPF to be very difficult to use. Luckily SSH is available on z/OS, so if I need to do Unix stuff I can just SSH in w…

> I find the Unix shell you access through ISPF to be very difficult to use. Hehe, I once ran tail(1) and forgot to enter the file name, so tail read from stdin, and Ctrl+D did not work, so my shell was stuck waiting for input until the system was IPL'ed. Fun times... ;-)

This is just between you and me, OK, but a couple of years back I managed to do something similar on an IBM i, in its QShell (AIX) environment. And it felt bad, too, because such an unrecoverable glitch is almost unheard of in iSeries land!

Re: Hello World on z/OS

#94

Post by sdkmvx »

SuperPaintMan wrote: post #54
Svip wrote: post #7

In the 'Allocate New Data Set' screenshot, it says - for the expiration date field - that the formats are 'YY/MM/DD, YYYY/MM/DD, YY.DDD, YYYY.DDD in Julian form, DDDD for retention periods in days or blank'. (I added some commas, which I assume are supposed to be there, but are just line breaks in the screenshot.) Does that mean z/OS supports the Julian calendar?

It does, In a similar vein Cobol has the ACCEPT DATE (YYMMDD) and ACCEPT DAY (YYDDD) constructs for retrieving the date. There's an optional argument for supporting four digit year codes however. Julian dates pop up in some wonky places across the system.

Are you sure?

Today is July 31, 2018 in the United States, which adopted the Gregorian calender per the act of British parliament entitled "An Act for Regulating the Commencement of the Year; and for Correcting the Calendar now in Use" (24 Geo. 2 c. 23) by skipping September 3-13, 1752 (obviously this was prior to the American revolution).

In the Julian calendar, there are leap days every four years. In the Gregorian calendar, there are leap years every four years except every 100 years except every 400 years. That is, 2000 and 2004 are leap years, but 1900 is not a leap year.

Since 100, 200, 300, 500, 600, 700, 900, 1000, 1100, 1300, 1400, 1500, 1700, 1800, and 1900 were leap years in the Julian calendar but not the Gregorian calendar, one must subtract 15 days to get to the Gregorian date to get the Julian date.

Today is July 18, 2018 in the Julian calendar.

The Soviet Union adopted the Gregorian calendar in 1918 by skipping February 1-13. They were the last. This is why the famous February revolution took place in March and why the October revolution took place in November. (Though I noticed Reuters announced it had been 100 years last year on the wrong day.)

Mainframes are weird, but I really doubt they don't use the Gregorian calendar whatever the text on the screen says.

Re: Hello World on z/OS

#95

Post by snuxoll »

forapurpose wrote: post #84
krylon wrote: post #59

Earlier quoted context omitted.

I have seen one PC-based server that had redundant RAM. I never tried pulling out RAM modules, but I guess there is not much point in having a RAID1-like arrangement for RAM if the machine cannot handle random RAM modules dying without crashing the OS. And it wasn't even a super high-end system.

> I have seen one PC-based server that had redundant RAM Yes, I've seen this too, and on lowish-end servers.

Memory mirroring is a pretty common feature on basically every x86 server I've used (going back to the Core 2-based Xeon's, no experience with older platforms), though I've never tried just yanking DIMM's out and wouldn't recommend trying it.

Re: Hello World on z/OS

#96

Post by southern_cross »

krylon wrote: post #52
wereHamster wrote: post #5

Earlier quoted context omitted.

Sure, that's certainly important to keep in mind. But that doesn't mean IBM shouldn't invest in usability.

I wonder why they haven't developed a more human-friendly successor to JCL. I get that IBM's all about backward compatibility, but would it kill them to add a more accessible alternative? I once spent three days figuring out how to deal with an invocation that did not fit in an 80-character line. sigh

There was OCL on the IBM S/34 and S/36 back in the day, and there's CL on the IBM i today, which dates back to the earliest S/38 days (circa 1978). It's been some decades now since I've dealt with JCL, but as I recall both of those other languages make JCL look like child's play in comparison. Also, don't forget about Rexx!

Re: Hello World on z/OS

#97

Post by dredmorbius »

walrus01 wrote: post #73
rbanffy wrote: post #63

Just a shameless plug: there is very little information in the form of Stack Overflow-like things and getting started with mainframes is, as this article shows, pretty hard. I made this SE proposal that's in commitment stage (where people commit to support the community). If you know about mainframes and are willing to be part of it, you should commit too. https://area51.stackexchange.com/proposals/118484/mainframes.…

The hard part for mainframes is that unlike Linux and the BSDs, you can't acquire a bunch of 4 year old Core i5 systems for $80 each (or sometimes free) and install a bunch of different OS varieties on them to test stuff in your home office or the bedroom of a bored teenager (example: centos hosting KVM VMs, debian + xen, freebsd on bare metal, etc).

C'mon, you just needa little motivation. ;-)

Here's What Happens When an 18 Year Old Buys a Mainframe

https://youtube.com/watch?v=45X4VP8CGtk

Re: Hello World on z/OS

#98

Post by southern_cross »

teh_klev wrote: post #40
AnIdiotOnTheNet wrote: post #14

> IBM uses special and completely unintuitive names for basic concepts…. because OF COURSE THEY DO. As I recall, it's called "Bluespeak", and that sort of thing is pretty common actually. I was educated in networking at a Cisco netacad, so I use Cisco terminology that is apparently not universal. Programming languages do this too for some reason: Sum type, tagged union, discriminated union, variant...

> IBM uses special and completely unintuitive names for basic concepts Once upon a time I worked as a (young) field engineer looking after mostly Intel based kit, peripherals and Novell/Windows/Unix OS support. Our company was subcontracted to look after a bunch of Perle controllers for another maintenance company that didn't have engineering staff locally (these were on two and four hour onsite must-fix contracts).…

Don't feel too bad. As a decades-long user of IBM gear, on and off, the VARY terminology has always struck me as quite odd, too.

Re: Hello World on z/OS

#99

Post by wolfgke »

binarycrusader wrote: post #72
wolfgke wrote: post #11

Earlier quoted context omitted.

> Linux and DOS/Windows have far more in common with each other than mainframe OSes, despite their huge differences, because they evolved from mini/microcomputers and UNIX. Surely Linux and the Windows NT line (don't confuse the Windows 9x line, which evolved indirectly from DOS with the Windows NT line) have much more in common with each other than mainframe OSes, but Windows did not evolve from UNIX: The Windows 9x…

Solaris has event ports which are equivalent to Windows IOCP. So not all *NIX systems are deficient in that regard :)

> Solaris has event ports which are equivalent to Windows IOCP. So not all *NIX systems are deficient in that regard :)

I know, but IOCP badly fits into the "UNIX philosophy", i.e. in this case how input/output is "typically" organized under UNIX.

Re: Hello World on z/OS

#100

Post by exolymph »

JdeBP wrote: post #31
AnIdiotOnTheNet wrote: post #14

> IBM uses special and completely unintuitive names for basic concepts…. because OF COURSE THEY DO. As I recall, it's called "Bluespeak", and that sort of thing is pretty common actually. I was educated in networking at a Cisco netacad, so I use Cisco terminology that is apparently not universal. Programming languages do this too for some reason: Sum type, tagged union, discriminated union, variant...

The point that M. Bellotti came close to, but missed, is that "of course they do" is because every field has jargon . The error here is in thinking that one set of jargon is intuitive and normal whilst another set of jargon is "special and completely unintuitive". The simple truth is that there are many people to whom jargon such as "WIMP", "ISOs", "flat UI", "IIFE", "DOM", "pull request", and "UX" is equally as opaq…

I recently started learning more about git in order to use GitHub for work. I can confirm that "pull request" makes no sense whatsoever before you have a working mental model of git (even now, I don't think I could adequately explain it to someone else).
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