test-drb

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101090 discussions

by jnc＠mercury.lcs.mit.edu

> From: Mouse > It's true that C is easy to use unsafely. ... I suspect it is not > possible to eliminate the ability to do stupid things in C without also > eliminating the ability to do some clever things in C. Oh so true. Computer science progress seems to be all about improving on getting the most bang for the buck (i.e. it's really engineering, which is all about bang/buck ratios - as the saying goes, 'an engineer is someone who can do for $.10 what any fool can do for $1'). So assembly language is maximally flexible, but very easy to screw up. Something like C gives you 93% of the flexibility, but with only 40% of the chances to screw up. (Numbers only approximate, after 2 seconds of consideration.) So further language development has had to improve on that ratio; ideally, one should decrease the latter with impacting the former, if possible - a non-trivial problem. And of course the optimal flexibility/screwage ratio will differ from programmer to programmer, and even from project to project. (I once wrote a condition handler package for C, and elected to do it in assembler - even though others have done in it C, using longjump(). But there are very few things where assembler seems a better choice, to me.) > Note that PDP-11 autoincrement and autodecrement exist only when > ... the pointers are in registers. Of course, clever programmers will make sure their code is arranged (not warped into an non-understandable maze, mind, just... arranged properly) to do that! :-) But to really do that effectively, you have to be able to control which variables are in registers, etc, etc. Modern optimizing compilers like to do this all for you - and do an incredibly good job, most of the time, to the point where for most programmers, the compiler does a _better_ job than they could. So, for 97% of programmers, probably the right thing. For those who are writing real-time code, know exactly what instructions any piece of code will compile into, and how many memory references are involved, not so much. (Back to different strokes for different programmers.) (Yes, yes, I know those optimizations often aren't portable - I wrote a fair amount of code that ran on several architectures at the same point in time. But what was optimal on one was usually pretty good on the others, too.) Noel

9 years, 7 months

OT: LED lighting configuration...

by wh.sudbrink＠verizon.net

Sorry for the OT post but I'm pretty sure someone here will know how this stuff works... An office near me was recently demolished/remodeled. It had retrofitted LED lighting in fluorescent fixtures. The remodelers were smart enough to save the "bulbs" but not smart enough to save the "ballasts" (DC power supplies). Once they figured out that they couldn't easily use them, they gave a bunch to me. I'd like to use them but I'm having a little trouble figuring out how. The "bulbs" are labeled: 15F18120-45 15 watt 36vdc constant current I'd like to put four in a fixture and I'm trying to understand what kind of driver I need and how to wire it. I was thinking of using a Mean Well LPF-60D-36 like this: http://www.ebay.com/itm/Mean-Well-LPF-60D-36-AC-DC-POWER-SUPPLY-Dimmable-LED -DRIVER-36V-60W-CLASS2-/161857068172?hash=item25af6edc8c:g:9hQAAOSwA4dWHVn5 and wiring the "bulbs" in parallel to it. But after realizing that I'm not completely sure what a "constant current" power supply does and doing a little "googling" I don't know if that's the right approach. Any help greatly appreciated, Bill S.

9 years, 7 months

Gentoo (was Re: strangest systems I've sent email from)

by alexmcwhirter＠triadic.us

I can more or less agree with your sentiments, but given the choice of needing to maintain compatibility between many applications and being able to support multiple architectures such as SPARC and Power Gentoo is really the only choice. The only real close candidate would be FreeBSD which treats anything that isn't x86 as a second class citizen. I have my own issues with Linux as well, and as I said earlier I would much rather use illumos, but when it comes to business applications that always have to run and always maintain compatibility is new versions come out gentoo is as close to a BSD/Unix that I can get to and maintain compatibility with everything I need. Use flags can be cumbersome if you have tons of applications such as a desktop system. But that's generally not the case for servers which is really all I care about in this case. For me it's generally just maintaining a set of used flags for each application that I need which is generally pretty minimal per server / container. Profiles help make Use flags not as cumbersome, but it doesn't quite fix the issue. Sent from my T-Mobile 4G LTE Device -------- Original message -------- From: Swift Griggs <swiftgriggs at gmail.com> Date: 4/29/2016 12:10 PM (GMT-05:00) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Subject: Gentoo (was Re: strangest systems I've sent email from) On Fri, 29 Apr 2016, alexmcwhirter at triadic.us wrote: > Gentoo is powerful because you get to chose your init system, kernel > options, and every other piece of software that runs on the box. Other than the swapping init systems, many OSS OS distributions have the ability to choose what you want to run. Not all are as granular as Gentoo (but some, say embedded distros, have even more control). There are dozens of Linux distros as you know, and this degree of control & granularity is one of the main variable. Ubuntu users want "just-worky-ness", Gentoo users often want tweakability in the extreme. It all depends on your needs and value system. > For example, dovecot on ubuntu pulls in ldap, sasl, etc... On gentoo you > choose what gets pulled in via USE flags. I guess there is no accounting for taste. I would not call USE flags a feature, my opinion is that they are painful in implementation (dragging around a list of way-too-many little keywords is not fun, IMHO), nasty to work with and have to look at (some giant wrap-around variables in the conf file), and make me feel dirty and disorganized. Plus, in my experience, if you accidentally put in two mutually exclusive or not-very-well-tested USE flags you are in for a hard time that might be difficult to track down (ie.. if the effects don't immediately surface). > CrossDev is also a great to that has helped me port gentoo to SPARC64 > with little to no issues. Cross compiling is neat, for sure. However, Gentoo doesn't have any unique claim on that (not that you implied that). Many other OSs have used the same methodology since long before Linux, much less Gentoo. -Swift

9 years, 7 months

Reproduction program pak boxes

by tlindner＠macmess.org

I just complete a project to reproduce some old game boxes. I got tired of the ripped and broken boxes I have for my Color Computer Program Paks. I made a video about it: https://youtu.be/5L9adQlM7ro -- -- tim lindner "Proper User Policy apparently means Simon Says."

9 years, 7 months

Very sad message: the passing of Jon Johnston

by hp-fix＠xs4all.nl

This morning I got the sad message of the passing of Jon Johnston the curator of the HP Museum website www.hpmusem.net. More info at : <http://www.heraldsun.com.au/news/victoria/father-of-three-jon-johnston-died -in-tibet-during-a-trek-in-the-himalayas/news-story/501c804577a833b0964016ba e87fd318> http://www.heraldsun.com.au/news/victoria/father-of-three-jon-johnston-died- in-tibet-during-a-trek-in-the-himalayas/news-story/501c804577a833b0964016bae 87fd318 Jon, was a fellow collector and HP enthusiast and will be missed. Jon himself and his site were a help and source of knowledge for everyone who was interested in HP computing history. -Rik

9 years, 7 months

Lyle scores a WIN for our hobby!

by jwest＠classiccmp.org

Several years ago, Lyle Bickley began negotiations with S&H Computer Systems to release TSX-Plus (a 3rd party Multiuser Operating System for PDP-11's) as free software for personal use. As is often the case, this process can take a lot longer than one would expect. Once Lyle obtained an initial agreement from the owner of TSX-Plus, he then had to await the approval from S&H's Board of Directors. Initially, S&H chose to only release the source code listings for TSX-Plus (which are now on Bitsavers.org). Unfortunately, the machine readable source code itself had been accidentally lost when S&H changed PDP-11 computer systems in-house. Eventually, Lyle was able to obtain the original SMD hard drive from S&H containing the latest versions of TSX-Plus, and the layered products COBOL-Plus and RTSORT (and other software that remains private to S&H Computer Systems). He transferred the TSX-Plus, COBOL-Plus, and RTSORT files to an RL02 disk - and using S&H's proprietary licensing software created a "personal use, serialized version" of TSX-Plus. This version has ALL the capabilities and features of the commercially licensed version of TSX-Plus. Subsequently, Lyle was authorized to release this "Personal Use" TSX-Plus distribution only to individuals that he could vouch for as being non-commercial users. After another year or so, he was able to obtain the current agreement and license to make this "Personal Use" TSX-Plus distribution generally available for non-commercial use. Please note that TSX-Plus is NOT public domain software; S&H retains all rights including ownership. They have provided a free personal use license available through Bickley Consulting West. There is still a paid commercial use license available directly from S&H. We all owe a big "Thanks!" to Harry Sanders at S&H Computer Systems and his Board of Directors for making this release a reality for all vintage computer folks! Also, the hobby owes huge thanks to Lyle Bickley for tirelessly pursuing this for us all! I've always been a huge fan of TSX-Plus and I'm thrilled there's now a personal (hobbyist) license thanks to Lyle. The distribution is at http://tsxplus.classiccmp.org Best, J

9 years, 7 months

basic switch lubricant

by chd＠chdickman.com

I have been cleaning a PDP-8/e front panel and some of the switches are not as free as others. The switches are simple slider basic switches. I have taken similar switches apart and noticed that there is a brown/red grease on the contacts. Any suggestions on the proper grease for a low voltage contact. Chuck

9 years, 7 months

Lyle scores a WIN for our hobby!

by wdonzelli＠gmail.com

Excellent news. Thank you for making this happen. -- Will On Apr 28, 2016 1:22 PM, "Jay West" <jwest at classiccmp.org> wrote: > > Several years ago, Lyle Bickley began negotiations with S&H Computer Systems > to release TSX-Plus (a 3rd party Multiuser Operating System for PDP-11's) as > free software for personal use. As is often the case, this process can take > a lot longer than one would expect. > > Once Lyle obtained an initial agreement from the owner of TSX-Plus, he then > had to await the approval from S&H's Board of Directors. Initially, S&H > chose to only release the source code listings for TSX-Plus (which are now > on Bitsavers.org). Unfortunately, the machine readable source code itself > had been accidentally lost when S&H changed PDP-11 computer systems > in-house. > > Eventually, Lyle was able to obtain the original SMD hard drive from S&H > containing the latest versions of TSX-Plus, and the layered products > COBOL-Plus and RTSORT (and other software that remains private to S&H > Computer Systems). He transferred the TSX-Plus, COBOL-Plus, and RTSORT files > to an RL02 disk - and using S&H's proprietary licensing software created a > "personal use, serialized version" of TSX-Plus. This version has ALL the > capabilities and features of the commercially licensed version of TSX-Plus. > > Subsequently, Lyle was authorized to release this "Personal Use" TSX-Plus > distribution only to individuals that he could vouch for as being > non-commercial users. > > After another year or so, he was able to obtain the current agreement and > license to make this "Personal Use" TSX-Plus distribution generally > available for non-commercial use. > > Please note that TSX-Plus is NOT public domain software; S&H retains all > rights including ownership. They have provided a free personal use license > available through Bickley Consulting West. There is still a paid commercial > use license available directly from S&H. > > We all owe a big "Thanks!" to Harry Sanders at S&H Computer Systems and his > Board of Directors for making this release a reality for all vintage > computer folks! Also, the hobby owes huge thanks to Lyle Bickley for > tirelessly pursuing this for us all! I've always been a huge fan of TSX-Plus > and I'm thrilled there's now a personal (hobbyist) license thanks to Lyle. > > The distribution is at http://tsxplus.classiccmp.org > > Best, > > J > >

9 years, 7 months

Lyle scores a WIN for our hobby!

by lbickley＠bickleywest.com

Hi All, Hopefully you all read in the "Notes" (and Jay's and my comments) that TSX-Plus requires RT-11 as a prerequisite. RT-11 is readily available all over the Internet. It is also available at on the classiccmp server at http://www.classiccmp.org/PDP-11/ Cheers, Lyle -- 73 AF6WS Bickley Consulting West Inc. http://bickleywest.com "Black holes are where God is dividing by zero"

9 years, 7 months

strangest systems I've sent email from

by jnc＠mercury.lcs.mit.edu

> From: Liam Proven > There's the not-remotely-safe kinda-sorta C in a web browser, > Javascript. Love the rant, which I mostly agree with (_especially_ that one). A couple of comments: > So they still have C like holes and there are frequent patches and > updates to try to make them able to retain some water for a short time, > while the "cyber criminals" make hundreds of millions. It's not clear to me that a 'better language' is going to get rid of that, because there will always be bugs (and the bigger the application, and the more it gets changed, the more there will be). The vibe I get from my knowledge of security is that it takes a secure OS, running on hardware that enforces security, to really fix the problem. (Google "Roger Schell".) > The Lisp Machines and Smalltalk boxes lost the workstation war. Unix > won, and as history is written by the victors Custom hardware for running LISP lost (not sure about Smalltalk, don't know much about it), I am quite sure, mostly because 'mainstream' CPUs got so much faster/cheaper, because of the volume. I saw this happening in the AI Lab at MIT: when you could run LISP on a workstation with a vanilla CPU much faster than a specialized LISP processor, that's all she wrote. (That effect killed all sorts of things, not just LISP machines, of course.) Noel

9 years, 7 months

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