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International conference: "Unix in Europe : between innovation, diffusion and heritage"

by Paloque-berges Camille

Dear THUS list, I am a recent lurker on this list, also a history and communication scholar looking at pieces of Unix history for my research. I hope it is okay if I share with you the news of a historical conference on Unix that we are organizing in France next Fall with fellow humanities scholars and computer scientists and engineers involved in the history and heritage of computing and computers. You are of course welcomed, even encouraged, to submit a proposal. It will be a pleasure to meet you at this conference in any case. Best, Camille Paloque-Berges *** Please find enclosed the CFP for the *international conference**"Unix in Europe: between innovation, diffusion and heritage"* that will take place in Cnam (Paris, France), October, 19th, 2017. A one-page abstract (maximum 500 words) with a short biography is expected for June 30th 2017. The Cfp is also available at : <http://technique-societe.cnam.fr/international-symposium-unix-in-europe-bet…>. Best regards, The organization comitee : Isabelle Astic, Raphaël Fournier-S'niehotta, Pierre-Eric Mounier-Kuhn, Camille Paloque-Berges, Loïc Petitgirard ------------------------------------------------------------ *Call for contributions* *International symposium * *Unix in Europe: between innovation, diffusion and heritage* */Conservatoire National des Arts et Métiers, Paris, France – October 19 2017/* ** Communications and discussions will be held in French or English. * * *Rationale* * * **The Unix system was born in the 1970s at the crossroads between two interacting worlds: industry (the Bell Labs at AT&T) and academia (the University of Berkeley computer science network). Its fast adoption throughout computer research and engineering networks across the world signaled the future success of the new system, fostering software experiments within its open, multi-user and multi-tasking system running on mini-computers – and later compatible with a larger part of computer hardware. In the European context, how was this American innovation propagated, adopted and adapted? Why was Unix of so much interest in this context, then and now? A solid culture of Unix users might also explain this success, as well as subsequent processes of appropriation and inheritance, due to the long and complex history of Unix versioning. The memory of Unix users is vivid indeed, fed by early accounts within the computer world (Salus, 1994) as well as preservation initiatives (Toomey, 2010). Moreover, the Unix system is a crucial reference in the history of computing, in particular in the field of free and open source software (Kelty, 2008), computer networks (Paloque-Berges, 2017), as well as in programming language philosophy (Mélès, 2013). In order to explore the variety of these interrogations, this symposium encourages contributions from historians as well as philosophers, social science researchers, and heritage professionals interested in the history of computer open systems and software with a focus on Unix or who have a wider perspective. It will also welcome protagonists and witnesses of Unix culture and carriers of its memory. We wish to discuss and shed light on several aspects of the development of Unix in Europe (including in comparison or relation with the rest of the world) along three main lines: historical and sociological, philosophical and epistemological, and heritage- and preservation-oriented. *1/ Historical and sociological perspectives* * * Historically, the Unix system is linked to the promotion and development in research on open systems and computer networks. How does this fit in the context of industrial, scientific and technological policies defined at the national and European level? The history of Unix thus reaches at least three levels of interrogations: 1/ the forms, places and practices of innovation around Unix in R&D labs and computing centers in companies, schools and universities; 2/ planning, promoting and negotiating open systems (norms and standards) from the perspective of science and/or politics; 3/ international geopolitical relations, whether economical or geopolitical and even geostrategic (for example between Unix users, with users of other computer equipment or other hardware and software companies, the role of embargos in the shipping of mini-computers, of code, and military uses of Unix). In parallel, how has the world of computer research welcomed, encouraged, negotiated and propagated uses and innovations related to Unix systems? This begs the question of how Unix-related research and development was legitimized - or played a part in the legitimization of computer science experimentalism in the scientific field and beyond. We would also like to highlight practices of resistance, the failure to acknowledge, ignorance of or even the limits of the Unix system, its software tools and hardware environment (beginning with the famous PDP and Vax machines from Digital Equipment where the first Unix versions were implemented). With a focus on occupational computer uses, we call for analysis which aims to explore and clarify: - the role of developers, users, and user associations – from the point of view of pioneers as well as helpers, maintainers and other witnesses of the implementation of Unix; - the context, process, and people who determined its propagation, appropriation, and development over time; - the meaning of concepts of Unix philosophy and ethics such as “openness” and “autonomy”, from a social, political or economic point of view. *2. Philosophical and epistemological perspectives* We will foster research and reflection at the crossroad of the theoretical foundations of computer systems and engineering pragmatism, between the philosophy of computer systems and Unixian practices. Protagonists in the conception and diffusion of Unix often claim to have a ‘Unix philosophy’ . But beyond statement of principle, what was the real influence of this idea on the technical choices underlying the system’s developments? What are the ethical, moral, and philosophical motivations – alongside the social, political or economic dimensions discussed earlier – underpinning the adoption of Unix or pretending to extend it (for instance in relation to the notions of sharing, modularity or freedom)? How is the idea of ‘openness’ attached to Unix practices and heritage (free software, open source) conceived? What are the theoretical developments to be drawn from it (for instance with the idea of open software)? The logical and mathematical foundations of Unix should be readdressed. Do the fundamental concepts of Unix have an ontological or metaphysical significance beyond the sole research aim of technical efficiency? What role do aesthetics play in the formulation of general principles and technical choices? How can we analyze programming languages such as C and its successors, scripts, software, and generally speaking, the proliferating source codes of Unix? How do we consider the system, the software environment, as well as the hardware in which Unix is implemented and executed? Such philosophical questions also cover the modalities of the transmission of Unix, extending to the investigation of the respective roles of theory and practice in the teaching of the system, the teaching of knowledge and tools underlying the system or supporting the system. *3. Unix heritage and ‘heritagization’* ** France is now the home to multiple initiatives taking place to build and preserve a material and immaterial heritage of computer science and technology – such as ‘Software Heritage’ at INRIA, a global software archive in progress. The Museum of Arts et Métiers gave impetus to the MINF initiative (‘Pour un Musée de l’informatique et du numérique’) and coordinates the ‘Patstec Mission’ dealing with contemporary scientific and technological heritage preservation, including computer science. At an international scale and with a grassroots perspective carried by the community of Unix users, the TUHS (The Unix Heritage Society) demonstrates the current interest in the specific heritage linked to Unix. We encourage reflections on this heritage and its specific features: - What is the place of Unix in the construction of computer science heritage? Is it possible to map Unix systems and their heritage, from the standpoint of machines, languages and software? What has already been collected? What corpus, data bases, and/or platforms with a patrimonial mission are concerned with Unix and to what purpose? - How are the questions of training, constitution and diffusion of a Unix culture incorporated in the effort to collect heritage? How do we evaluate and put forward the importance of immaterial heritage attached to Unix, considering the effects of community and memory in its history and for the writing of its history? - What are the practices and modalities advocated by the unixian heritage itself? What has been its influence on the field of computer engineering and research as well as diverse fields such as: popularization of science and technology, ‘hacker’ movements and many ‘maker’ practices today (Lallement, 2016)? *Schedules* Please send a one-page abstract (maximum 500 words) with a short biography by June 30, 2017 to: camille.paloque-berges(a)cnam.fr <mailto:camille.paloque-berges@lecnam.net>and loic.petitgirard(a)cnam.fr <mailto:loic.petitgirard@cnam.fr>. Accepted contributions and speakers will be notified by July 15, 2017. *Organizing committee* Isabelle Astic (Musée des arts et métiers) Raphaël Fournier-S’niehotta (Cédric, Cnam) Pierre-Eric Mounier-Kuhn (CRM, Paris 1) Camille Paloque-Berges (HT2S, Cnam) Loïc Petitgirard (HT2S, Cnam) *Scientific committee * François Anceau (UMPC-LIP6)** Pierre Cubaud (Cédric, Cnam) Liesbeth de Mol (STL, Lille 3) Claudine Fontanon (CAK, EHESS) Gérald Kembellec (DICEN, Cnam) Baptiste Mélès (Archives Henri Poincaré, CNRS) Pierre Paradinas (Cédric, Cnam, SIF) Giuseppe Primiero (Middlesex University) Lionel Tabourier (LIP6, Paris 6)** *Institutional partners and support: * - Project « Hist.Pat.info.Cnam », HT2S, Cnam – Research program supported by the Excellence laboratory History and Anthropology of Knoweldge, Technics and Beliefs (HASTEC), and in partnership with the laboratories CEDRIC (Cnam), DICEN (Cnam), and the Center Alexandre Koyré (EHESS). - « Histoire de l’informatique » (« History of computing » seminar) seminar - (Musée des arts et métiers, CRM, Paris 1, UMPC-LIP6) - « Source code » seminar - (CNRS, Cnam, Université Paris 6). With support from the DHST/DLMPST for the History and Philosophy of Computing (HAPOC) *Bibliography * Kelty, Christopher M. 2008. /Two Bits: The Cultural Significance of Free Software/. Durham: Duke University Press Books. Lallement, Michel. 2016. /L’âge du faire, /Seuil. Mélès, Baptiste. 2003. « Unix selon l’ordre des raisons : la philosophie de la pratique informatique ». /Philosophia Scientiæ/17 (3): 181‑98. Salus, Peter H. 1994. /A quarter century of UNIX/. Addison-Wesley. Reading. Toomey, Warren. 2010. « First Edition Unix: Its Creation and Restoration ». /IEEE Annals of the History of Computing/ 32 (3): 74‑82. * * **

8 years

Re: [TUHS] 211bsd: kernel panic after a 'here document' in tcsh

by jnc＠mercury.lcs.mit.edu

> From: "Walter F.J. Mueller" > the kernel panic after tcsh here documents is understood. Very nice detective work! > The kernel panic is due to a coding error in mch_fpsim.s. ... After > fixing the "$SIGILL." ... and three similar cases I'm fairly amazed that apparently nobody has run across one of these 4 before! (Or, at least, not bothered to report it.) I wonder how long that bug has been in the code? Noel

8 years

Re: [TUHS] 211bsd: kernel panic after a 'here document' in tcsh

by Johnny Billquist

On 2017-06-11 04:00, "Walter F.J. Mueller" <w.f.j.mueller(a)retro11.de> wrote: > Hi, > > the kernel panic after tcsh here documents is understood. > And fixed, at least on my system. Nice work. Looking forward to patch #250. And to respond to Noels remark about this being around for a long time without reports - since this is in FPSIM, and I believe the notes for 2.11BSD even says that this is an untested piece of code, which are not even know if it works or not, it's not something that have been used for ages. I'm in a way surprised it even worked at all. I think I've seen somewhere that it was last tested around 2.9BSD, and have not been officially tested since. > The essential hint was Johnny's observation that on his system he gets > an "Illegal instruction - core dumped" and no kernel panic. Well, had I had FPP simulated, I would maybe not have gotten a kernel panic anyway. It would all depend on where the address ended up. With my current build, the kernel would have been able to read the address, since it pointed into the boot diagnostics rom. So it's a dicey error at best. But the tcsh error was very good that you also figured out. And I guess it means we now have a known working FPSIM. :-) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

8 years

Array index history

by Doug McIlroy

> Who started this? Why was the change made? Arrays in Fortran and Algol were indexed from 1 by default, but Algol (IIRC) generalized that to allow first:last declarations. NPL used first,last for the SUBSTR operation. But first,last begets off-by-one errors. The successor slice begins at last+1. The formula for the position of 1-indexed a[i,j] is a mess. First,length is much cleaner: the successor begins at first+length. I convinced the committee of that, so when NPL became PL/I, first,length was the convention. Zero- indexing is also a clean first,length notation. BCPL, where a[i] was synonymous with rv(a+i), had it. Dennis, who knew a good thing when he saw it, took it over. Dijkstra, too, often inveighed against 1-indexing, and opined that zero was the true computer-science way. 1-indexing certainly came into programming languages from the math tradition for matrix notation. Of course in math series are often indexed from zero, so one may pick and choose. Off hand I can only think of one CS context where 1 comes in handy: heapsort. Doug

8 years

Re: [TUHS] 211bsd: kernel panic after a 'here document' in tcsh

by Walter F.J. Mueller

Hi, the kernel panic after tcsh here documents is understood. And fixed, at least on my system. The essential hint was Johnny's observation that on his system he gets an "Illegal instruction - core dumped" and no kernel panic. I'm using a self-build PDP 11/70 on an FPGA, see https://github.com/wfjm/w11/ https://wfjm.github.io/home/w11/ which doesn't have a floating point unit. Therefore the kernel is build with floating point emulation, thus with FPSIM YES # floating point simulator In a kernel with FPSIM activated the trap handler trap(), see http://www.retro11.de/ouxr/211bsd/usr/src/sys/pdp/trap.c.html calls for each user mode illegal instruction trap fpsim(). In case it was a floating point instruction fpsim() emulates it, returns 0, and trap() simply returns. If not, fpsim() returns the abort signal type, and trap() calls psignal() with this signal type, which in general will terminate the offending process. The kernel panic is due to a coding error in mch_fpsim.s. Look in http://www.retro11.de/ouxr/211bsd/usr/src/sys/pdp/mch_fpsim.s.html the code after label badins: badins: / Illegal Instruction mov $SIGILL.,r0 br 2b The constant SIGILL is defined in assym.h as #define SIGILL 4. Thus after substitution the mov instruction is mov $4..,r0 with *two dots* !!! The 'as' assembler generates from this mov #160750,r0 So r0 will contain a invalid signal number, which is returned by fpsim() to trap(). This signal number is passed to psignal(), which starts with mask = sigmask(sig); prop = sigprop[sig]; The access to sigprop[sig] results into an address in IO space, causes an UNIBUS timeout, and in consequence the kernel panic. After fixing the "$SIGILL." to "$SIGILL" (removing the extraneous '.') and three similar cases the kernel doesn't panic anymore, tcsh crashed with an illegal instruction trap. Remains the question why tcsh runs onto an illegal instruction. Getting now a tcsh core dump adb gives the answer adb tcsh tcsh.core $c 0172774: _rscan(0176024,0174434) from ~heredoc+0246 0176040: _heredoc(067676) from ~execute+0234 0176126: _execute(067040,01512,0,0) from ~execute+03410 0176222: _execute(066754,01512,0,0) from ~process+01224 0176274: _process(01) from ~main+06030 0177414: _main() from start+0104 heredoc(), which is located in OV1, calls rscan(), which is in OV6 with rscan(Dv, Dtestq); where Dtestq is a function pointer to Dtestq(), which is as heredoc() in OV1. rscan(), which has the signature rscan(t, f) register Char **t; void (*f) (); uses 'f' in the statement (*f) (*p++); The problem is that - heredoc() and Dtestq() are in OV1 - that's why in the end ~Dtestq is used a function pointer, like for all overlay internal function invocations - rscan() is in OV6, when it's called, overlay is switched OV1 -> OV6 - this invalidates the function pointer, which points to some random code location, which happens to hold '000045', causing a trap. It is clear that in this context _Dtestq, the forwarder in the base, must be used and not ~Dtestq, the entry point in the overlay. The generated code for 'rscan(Dv, Dtestq)' is ~heredoc+0230: mov $0174434,(sp) # arg Dtestq: uses ~Dtestq ~heredoc+0234: mov r5,-(sp) ~heredoc+0236: add $0177764,(sp) # arg Dv ~heredoc+0242: jsr pc,*$_rscan Since rscan() is very small and only used by heredoc() I simply moved the code of rscan() from sh.glob.c (OV6) to sh.dol.c where also heredoc() and Dtestq() is defined. After that tcsh works fine with here documents ./tcsh cat >x.x <<EOF 1 $TERM $PWD EOF cat x.x 1 vt100-long /usr/src/bin/tcsh Bottom line - fpsim was broken all the time - tcsh was broken all the time I'm convert this into proper patches and send them to Steven, but this will take some time because I've to tidy up my system to be again in the position to provide proper and clean patch sets. With best regards, Walter P.S.: debugging the kernel issue was quite easy because the w11a CPU has three essential 'build into the cpu' debug tools: - a 'cpu monitor', which records 144 bits of processor state for the last 256 instructions or vector fetches, see https://github.com/wfjm/w11/blob/master/rtl/w11a/pdp11_dmcmon.vhd - a 'breakpoint unit' which allows to set instruction of data breakpoints - an 'ibus monitor' which records the last 512 ibus transactions After setting a breakpoint on the trap 004/010 handler an inspection of the instruction trace gave the essential information. Below a very condensed and annotated excerpt nc ....pc cprptnzvc ..dsrc ..ddst ..dres vmaddr vmdata # # the "(*f) (*p++)" in tcsh, running onto an illegal instruction # 15 145210 uu00-.... 000105 173052 000105 w d 173052 000105 mov r0,(sp) 25 145212 uu00-.... 173050 174434 174434 w d 173050 145216 jsr pc,@n(r5) 19 174434 uu00-.... 000010 173064 000010 r i 174434 000045 ?000045? 1 174434 uu00-.... 000012 173064 000012 r d 000010 000045 !VFETCH 010 RIT # # the "mov $SIGILL.,r0" in fpsim(), load 160750 instead of 000004 # 17 160744 ku00-n..c 160750 000045 160750 r i 160746 160750 mov #n,r0 14 160750 ku00-n..c 160752 160750 160732 r i 160750 000770 br .-14 # # the "sigprop[sig]" access in psignal(), which accesses 174036 # which leads to a external bus (or UNIBUS) time out and IIT trap # 23 161314 ku00-.z.. 000000 147500 000000 w d 147500 000000 mov r1,n(r5) 9 161320 ku00-.z.. 174036 000000 000000 Ebto 174036 013066 movb n(r3),r0 3 161320 ku00-.z.. 000006 000000 000006 r d 000004 013066 !VFETCH 004 IIT

8 years

Re: [TUHS] Array index history

by David

Arnold gets it right on the Pascal indexing. In UCSD Pascal you could specify any array bounds you would like and the compiler would 0 base them for you by always doing a subtraction, or addition if your min was negative, of your min array index. So a little run time cost for non-zero based arrays. I’m not sure how other Pascal compilers did this. I find it interesting that there are now a slew of testing programs (Valgrind, Address Sanitizer, Purify, etc) that will add the ‘missing’ array bounds checking for C. David > On Jun 7, 2017, at 10:01 AM, tuhs-request(a)minnie.tuhs.org wrote: > > Date: Wed, 07 Jun 2017 07:20:43 -0600 > From: arnold(a)skeeve.com > To: tuhs(a)tuhs.org, ag4ve.us(a)gmail.com > Subject: Re: [TUHS] Array index history > Message-ID: <201706071320.v57DKhmJ026303(a)freefriends.org> > Content-Type: text/plain; charset=us-ascii > > Pascal (IIRC) allowed you to specify upper and lower bounds, something > like > > foo : array[5..10] of integer; > > with runtime bounds checking on array accesses. (I could be wrong --- > it's been a LLLLOOONNNGGG time.) > > HTH, > > Arnold

8 years

Re: [TUHS] Array index history

by Johnny Billquist

On 2017-06-07 19:01, "Ron Natalie"<ron(a)ronnatalie.com> wrote: > The original FORTRAN and BASIC arrays started indexing at one because everybody other than computer scientists start counting at 1. FORTRAN, yes. BASIC (which dialect might we be talking about?) normally actually start with 0. However, BASIC is weird, in that the DIM statement is actually specifying the highest usable index, and not the size of the array. Thus: DIM X(10) means you get an array with 11 elements. So, people who wanted to use array starting at 1 would still be happy, and if you wanted to start at 0, that also worked. You might unintentionally have a bit of wasted memory, though. > These languages were for scientists and the beginner, so you wanted to make things compatible with their normal concepts. True. > PASCAL on the other hand required you to give the minimum and maximum index for the array. In a way, PASCAL makes the most sense. You still what range you want, and you get that. Anything works, and it's up to you. That said, PASCAL could get a bit ugly when passing arrays as arguments to functions because of this. > Of course, C’s half-assaed implementation of arrays kind of depends on zero-indexing to work. :-) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

8 years

Re: [TUHS] 211bsd: kernel panic after a 'here document' in tcsh

by Johnny Billquist

On 2017-06-07 22:14, "Walter F.J. Mueller"<w.f.j.mueller(a)retro11.de> wrote: > Hi, > > a few remarks on the feedback on the kernel panic after a 'here document' in tcsh. > > To Michael Kjörling question: > > I'm curious whether the same thing happens if you try that in some > > other shell? (Not sure how widely here documents were supported back > > then, but I'm asking anyway.) > And Johnny Billquist remark > > Not sure if any of the other shells have this. > > 'here documents' are available and work fine in sh and csh. > And are in fact used, examples Ah. Thanks. Too lazy to check. > To Michael Kjörling remark > > The PC value in the panic report ("pc 161324") strikes me as high > and Johnny Billquist remark > > This is in kernel mode, and that is in the I/O page. > > 211bsd uses split I/D space and uses all 64 kB I space for code. D'oh! Color me stupid. I should have thought of that. > The top 8 kB are in fact the overlay area, and the crash happened > in overlay 4 (as indicated by ov 4). With a simple > > nm /unix | sort | grep " 4" > > one gets > > 161254 t ~psignal 4 > 162302 t ~issignal 4 > > so the crash is just 050 bytes after the entry point of psignal. So the > PC address is fine and not the problem. For psignal look at > > http://www.retro11.de/ouxr/211bsd/usr/src/sys/sys/kern_sig.c.html#s:_psignal > > the crash must be one of the first lines. psignal is an internal kernel > function, called from > > http://www.retro11.de/ouxr/211bsd/usr/src/sys/sys/kern_sig.c.html#xref:s:_p… > > and has nothing to do with the libc function psignal > > http://www.retro11.de/ouxr/211bsd/usr/man/cat3/psignal.0.html > http://www.retro11.de/ouxr/211bsd/usr/src/lib/libc/gen/psignal.c.html The libc function would be in user mode, so that one was pretty clear. Ok. Digging through this a little for real then. psignal gets called with a signal from the trap handler. The actual signal is weird. It would appear to be 0160750, which would be -7704 if I'm counting right. That does not make sense as a signal. The psignal code pulls a value based on the signal number, which is the line: prop = sigprop[sig]; which uses the signal number as an index. With a random, weird signal number, this access wherever that might end up. Which is when you get the crash. On my system, sigprop is at address 0012172, which, with a signal of -7704 ends up at address 0173142, which by (un)luck happens to be in the middle of the diagnostics bootstrap rom space. So I don't get a Unibus timeout error, while you do. Probably because sigprop is at a slightly different address in your kernel. So, the real question is how trap can be calling psignal with such a broken signal number. I might dig further down that question another day. But unless you already got this far, I might have saved you a few minutes of digging. I did start looking into the trap code, which is in pdp/trap.c, but this is not entirely straight forward. It goes through a bunch of things trying to decide what signal to send, before actually calling psignal. > To Johnny Billquist remark > > Could you (Walter) try the latest version of 2.11BSD and see if you > > still get that crash? > > very interesting that you see a core dump of tcsh rather a kernel panic. Indeed. > Whatever tcsh does, it should not lead to a kernel panic, and if it does, > it is primarily a bug of the kernel. It looks like there are two issues, > one in tcsh, and one in the kernel. I've a hunch were this might come from, > but that will take a weekend or two to check on. Agree that the kernel should not crash on this. Also, tcsh should not really crash either, but it's a separate issue, even though one might have triggered the other here. But yes, there are two bugs in here. If you can recreate the kernel crash on the latest version, that would be good. But it smells like trap.c have some path where it does not even set what signal to deliver, and then calls psignal with whatever the variable i got at the function start. Which would be some random stuff on the stack. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

8 years

Re: [TUHS] Array index history

by Johnny Billquist

On 2017-06-08 22:17, Dave Horsfall<dave(a)horsfall.org> wrote: > > Just to diverge from this thread a little, it probably isn't all that > remarkable that programming languages tend to reflect the hardware for > which they were designed. > > Thus, for example, we have the C construct: > > do { ... } while (--i); > > which translated right into the PDP-11's "SOB" instruction (and > reminiscent of FORTRAN's insistence that DO loops are run at least once > (there was a CACM article about that once; anyone have a pointer to it?)). > > And of course the afore-mentioned FORTRAN, which really reflects the > underlying IBM 70x architecture (shudder). FORTRAN stopped running the loops at least once already with FORTRAN 77. The last who insisted on running loops at least once was FORTRAN IV. Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt(a)softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

8 years

Array index history

by shawn wilson

I learned the other day that array indexes in some languages start at 1 instead of 0. This seems to be an old trend that changed around the 70s? Who started this? Why was the change made? It seems to have come about around the same time as C, but interestingly enough Lua is kinda in between (you can start an array at 0 or 1). Smalltalk can probably have a 0 base index just by it's nature, but I wonder whether that would work in a 40 year old interpreter.

8 years

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TUHS