Software bloat (Larkin was right)
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From: krw on 22 May 2010 10:52 On Fri, 21 May 2010 22:49:48 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Fri, 21 May 2010 23:42:17 -0500, "krw(a)att.bizzzzzzzzzzzz" ><krw(a)att.bizzzzzzzzzzzz> wrote: > >>On Fri, 21 May 2010 19:27:11 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Fri, 21 May 2010 17:40:55 -0700, D Yuniskis >>><not.going.to.be(a)seen.com> wrote: >>> >>>>Hi John, >>>> >>>>John Larkin wrote: >>>>> On Fri, 21 May 2010 09:40:00 -0700, D Yuniskis >>>>> <not.going.to.be(a)seen.com> wrote: >>>>> >>>>>> Hi Phil, >>>>>> >>>>>> Phil Hobbs wrote: >>>>>>> On 5/20/2010 2:03 PM, D Yuniskis wrote: >>>>>>>> This, I think, is an outgrowth of the same sort of >>>>>>>> ridiculous mindset that people initially bring to >>>>>>>> *organizing* data. E.g., how many part numbering systems >>>>>>>> have data embedded *in* the part number that tries to >>>>>>>> describe the item? (isn't that the role of the *description* >>>>>>>> tied to the P/N??) People impose structure on things >>>>>>>> unnecessarily instead of letting the machine do that on >>>>>>>> their behalf. >>>>>>>> >>>>>>>> E.g., when I started preparing documents, standards, etc. >>>>>>>> here, I used a much more commonsense approach: I started >>>>>>>> with *1* :> (instead of something artificial like >>>>>>>> 1985-SPEC-SFW-001.1 -- the ".1" being a revision level, etc.) >>>>>>>> Then, moved on to "2". >>>>>>>> >>>>>>>> Data should largely be free-form -- except where it *can't* :> >>>>>>>> This applies to part numbers, object (file) names, etc. Once >>>>>>>> you start imposing artificial structure, you start forcing >>>>>>>> things to be "done your way" -- which, typically, exposes >>>>>>>> some *flaw* in "your way", later (once you are *very* pregnant!) >>>>>>>> >>>>>>>> Put smarts in the system to be able to *understand* the data. >>>>>>> It's sort of nice to be able to look at a part number and see whether >>>>>>> it's a capacitor or a BNC connector, though. That doesn't have to have >>>>>>> descriptions embedded in the part number, but it does need a bit of >>>>>>> thought, e.g. numbers starting with '0' are subassemblies, '1', >>>>>>> resistors, '2', capacitors, and so forth. Takes an extra couple of >>>>>>> digits but makes life a lot easier. >>>>>> I don't think it works, in the long run. And, I think >>>>>> the effort spent trying to figure out *how* to do this >>>>>> (and codifying it and ensuring everyone uses the same >>>>>> rules) is better used getting better descriptions, better >>>>>> search capabilities, etc. >>>>> >>>>> It is convenient to have all the 0805 resistors in the same part of >>>>> the stockroom, and not mixed randomly with transformers and sheet >>>>> metal and shrink tubing. Even more convenient to have them in order by >>>>> resistance. >>>> >>>>There's nothing that says part numbers have to be positioned >>>>on shelves in sequential order. You track the *location* >>>>of a part as part of your inventory control system. So >>>>that you are free to put things wherever is most convenient. >>> >>>Cool. Every part gets a location number that determines their location >>>and order on the shelves. So why isn't that the part number? >> >>...and if you change the inventory location you change all your schematics. If >>you obsolete a part you can never use that shelf again? > >A schematic is a reference drawing that doesn't control anything; it >refers to parts by reference designator. Assembly drawings and their >associated parts lists control product configuration, and they use >part numbers. I'm surprised I have to explain stuff this basic. Our schematic controls the BOM (guarantees that they're in sync). The "assembly drawings" are for inspection use only; pick-n-place machines can't read them. >What doesn't surprise me, any more, is what a horror most material and >document control systems are. You didn't answer the other questions. What do you do with obsolete part numbers? Leave a shelf empty for eternity? What happens with a new part that similar to other parts. Move everything in your stockroom to make room for it? Why isn't your street address your name?
From: krw on 22 May 2010 10:53 On Sat, 22 May 2010 01:13:02 -0500, "Tim Williams" <tmoranwms(a)charter.net> wrote: >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >news:i0gev5ltreatfl8mk6s1ga6a2m9nl1shu3(a)4ax.com... >>>There's nothing that says part numbers have to be positioned >>>on shelves in sequential order. You track the *location* >>>of a part as part of your inventory control system. So >>>that you are free to put things wherever is most convenient. >> >> Cool. Every part gets a location number that determines their location >> and order on the shelves. So why isn't that the part number? > >Bicker, bicker. > >Concatenate both numbers, hash them, and use the hash code. > >The number is completely devoid of meaning, and offers instant access to its >field in the database. ....and creates the worst of both alternative. >This satisfies both parties, debate over. ;-) You *must* be a Pelosi Demonicrat.
From: Didi on 22 May 2010 12:00 On May 21, 9:03 pm, D Yuniskis <not.going.to...(a)seen.com> wrote: > >> ... > >> My TCP/IP stack is over 100 files and a couple of megabytes of > >> source (C with a tiny mix of ASM). > > > Into how much object code does that compile? Seems comparable > > It depends on which options I support, how defensive I > want the code to be (i.e., what attacks it will thwart), > what services I want to include, etc. I can build it > (actually, i have several different stacks developed > over the years for various different criteria) in a lot > of different ways depending on the hardware and software > (OS) resources available. > > For example, does the NIC have support for hardware checksums? > Or, do I have to do it in software? Or, skip them entirely?? > Support for multiple interfaces? Packet forwarding? > Routing protocols? How many sockets? Zero-copy semantics? > etc. > > I can come up with a "usable" stack (single interface) in > as little as ~60KB if I "try hard". Of course we have no chance to compare apples to apples, but perhaps we could get some feeling. I was more after a "fullblown" thing, the directory list I posted does it "all", tcp & udp checksum, crc16 & 32 (for ppp), defaults to a 512 simultaneous connections (never used up so far :-) ), generally you get a stack a "normal" OS would expect. "Zero copy" is never really quite zero, but to the extent reasonable I am doing it. Incoming tcp data will get copied once if the application asks for it just "somewhere" in its memory space, I know of no other sane way of doing it. Packets can also be accessed raw, of course, but normally tcp is about having an uninterrupted stream. Outgoing data are not copied at all if the hardware will allow it (on the mpc5200 it does, except IIRC for tiny packets where it was impractical to pursue). Dimiter ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/
From: Michael A. Terrell on 22 May 2010 12:12 "krw(a)att.bizzzzzzzzzzzz" wrote: > > On Fri, 21 May 2010 22:49:48 -0700, John Larkin > <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > > >On Fri, 21 May 2010 23:42:17 -0500, "krw(a)att.bizzzzzzzzzzzz" > ><krw(a)att.bizzzzzzzzzzzz> wrote: > > > >>On Fri, 21 May 2010 19:27:11 -0700, John Larkin > >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >> > >>>On Fri, 21 May 2010 17:40:55 -0700, D Yuniskis > >>><not.going.to.be(a)seen.com> wrote: > >>> > >>>>Hi John, > >>>> > >>>>John Larkin wrote: > >>>> > >>>>There's nothing that says part numbers have to be positioned > >>>>on shelves in sequential order. You track the *location* > >>>>of a part as part of your inventory control system. So > >>>>that you are free to put things wherever is most convenient. > >>> > >>>Cool. Every part gets a location number that determines their location > >>>and order on the shelves. So why isn't that the part number? > >> > >>...and if you change the inventory location you change all your schematics. If > >>you obsolete a part you can never use that shelf again? > > > >A schematic is a reference drawing that doesn't control anything; it > >refers to parts by reference designator. Assembly drawings and their > >associated parts lists control product configuration, and they use > >part numbers. I'm surprised I have to explain stuff this basic. > > Our schematic controls the BOM (guarantees that they're in sync). The > "assembly drawings" are for inspection use only; pick-n-place machines can't > read them. > > >What doesn't surprise me, any more, is what a horror most material and > >document control systems are. > > You didn't answer the other questions. What do you do with obsolete part > numbers? Leave a shelf empty for eternity? What happens with a new part that > similar to other parts. Move everything in your stockroom to make room for > it? We removed empty bins for deleted stock numbers. There was a slot left empty every so often, to allow for expansion. Between the two, the shelves only got reset during the slow season. A lot of designs went from through hole to surface mount. Strange as it may seem, we gained space on the resistor and capacitor shelves for the same level of stock numbers. :) -- Anyone wanting to run for any political office in the US should have to have a DD214, and a honorable discharge.
From: John Larkin on 22 May 2010 13:45
On Sat, 22 May 2010 09:52:14 -0500, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >On Fri, 21 May 2010 22:49:48 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Fri, 21 May 2010 23:42:17 -0500, "krw(a)att.bizzzzzzzzzzzz" >><krw(a)att.bizzzzzzzzzzzz> wrote: >> >>>On Fri, 21 May 2010 19:27:11 -0700, John Larkin >>><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Fri, 21 May 2010 17:40:55 -0700, D Yuniskis >>>><not.going.to.be(a)seen.com> wrote: >>>> >>>>>Hi John, >>>>> >>>>>John Larkin wrote: >>>>>> On Fri, 21 May 2010 09:40:00 -0700, D Yuniskis >>>>>> <not.going.to.be(a)seen.com> wrote: >>>>>> >>>>>>> Hi Phil, >>>>>>> >>>>>>> Phil Hobbs wrote: >>>>>>>> On 5/20/2010 2:03 PM, D Yuniskis wrote: >>>>>>>>> This, I think, is an outgrowth of the same sort of >>>>>>>>> ridiculous mindset that people initially bring to >>>>>>>>> *organizing* data. E.g., how many part numbering systems >>>>>>>>> have data embedded *in* the part number that tries to >>>>>>>>> describe the item? (isn't that the role of the *description* >>>>>>>>> tied to the P/N??) People impose structure on things >>>>>>>>> unnecessarily instead of letting the machine do that on >>>>>>>>> their behalf. >>>>>>>>> >>>>>>>>> E.g., when I started preparing documents, standards, etc. >>>>>>>>> here, I used a much more commonsense approach: I started >>>>>>>>> with *1* :> (instead of something artificial like >>>>>>>>> 1985-SPEC-SFW-001.1 -- the ".1" being a revision level, etc.) >>>>>>>>> Then, moved on to "2". >>>>>>>>> >>>>>>>>> Data should largely be free-form -- except where it *can't* :> >>>>>>>>> This applies to part numbers, object (file) names, etc. Once >>>>>>>>> you start imposing artificial structure, you start forcing >>>>>>>>> things to be "done your way" -- which, typically, exposes >>>>>>>>> some *flaw* in "your way", later (once you are *very* pregnant!) >>>>>>>>> >>>>>>>>> Put smarts in the system to be able to *understand* the data. >>>>>>>> It's sort of nice to be able to look at a part number and see whether >>>>>>>> it's a capacitor or a BNC connector, though. That doesn't have to have >>>>>>>> descriptions embedded in the part number, but it does need a bit of >>>>>>>> thought, e.g. numbers starting with '0' are subassemblies, '1', >>>>>>>> resistors, '2', capacitors, and so forth. Takes an extra couple of >>>>>>>> digits but makes life a lot easier. >>>>>>> I don't think it works, in the long run. And, I think >>>>>>> the effort spent trying to figure out *how* to do this >>>>>>> (and codifying it and ensuring everyone uses the same >>>>>>> rules) is better used getting better descriptions, better >>>>>>> search capabilities, etc. >>>>>> >>>>>> It is convenient to have all the 0805 resistors in the same part of >>>>>> the stockroom, and not mixed randomly with transformers and sheet >>>>>> metal and shrink tubing. Even more convenient to have them in order by >>>>>> resistance. >>>>> >>>>>There's nothing that says part numbers have to be positioned >>>>>on shelves in sequential order. You track the *location* >>>>>of a part as part of your inventory control system. So >>>>>that you are free to put things wherever is most convenient. >>>> >>>>Cool. Every part gets a location number that determines their location >>>>and order on the shelves. So why isn't that the part number? >>> >>>...and if you change the inventory location you change all your schematics. If >>>you obsolete a part you can never use that shelf again? >> >>A schematic is a reference drawing that doesn't control anything; it >>refers to parts by reference designator. Assembly drawings and their >>associated parts lists control product configuration, and they use >>part numbers. I'm surprised I have to explain stuff this basic. > >Our schematic controls the BOM (guarantees that they're in sync). The >"assembly drawings" are for inspection use only; pick-n-place machines can't >read them. We make dash number versions of assemblies, which includes functional variants and customizations for particular customers. So the values on a schematic are not guaranteed to be correct, and all the shown parts may not be stuffed. Schematic 22S470B is a reference drawing for PCB fab drawing 22D470B and assembly drawing 22A470B. The assembly drawing may in turn have multiple associated parts lists for different dash numbers, a parts list being a file like 22A470.12B for the physical entity 22A470-12B. An ECO or test procedure or manual states which assemblies it applies to. Everything lives on a server. Once a product drawing set rev A is released to the server, we never change it; the next set will be rev B. If we need to make a small change to the rev A stuff, we do that by ECO. We can create a new dash number of any product, at any time, by creating a new parts list, which can reference any new drawings or procedures that might have been created. This is pretty much standard military/aerospace policy, with our own non-random way of naming drawings and assemblies. It works great. People without the mil/aero tradition tend to make up all sorts of dangerous fuzzy stuff. When you build airplanes, things need to be kept under control, and configuration must be absolutely known. If we find a bug in a design, we need to know the exact configuration and status of every unit in the field, so we can alert the customers and fix the ones that need it. Or if a customer returns a unit for cal or repair, we need to exactly understand its version and history. > >>What doesn't surprise me, any more, is what a horror most material and >>document control systems are. > >You didn't answer the other questions. What do you do with obsolete part >numbers? If a part might be needed for a repair, we keep some in stock. One of our selling points is that we will build or repair anything, no matter how old, as long as we possibly can. If a part is truly dead, we physically "retire" it to a section of the basement. You never know if engineering will want to play with one. If it's a real klunker, essentially scrap metal, we get rid of it. We never reuse a stock number. It stays in the database, with a note like "retired" or "buggy:do not use". There's a folder associated with each part where we park datasheets, photos, app notes, measurements, purchasing notes, rants, anything we want to remember. >Leave a shelf empty for eternity? Most parts are small. 10-20 bins go on a shelf. Or roughly 40 reels. We put parts on shelves. We have some empty shelves, mostly the less accessable high and low ones, because we planned for expansion. What happens with a new part that >similar to other parts. Move everything in your stockroom to make room for >it? Sure. We leave some spare space on every shelf. If a shelf overflows, you have to shuffle a little, which might take 45 seconds to do. We have a materials/purchasing person who does all that management. A stockroom isn't a graveyard with fixed plots. But the parts are always in physical order by stock number, with big bold labels on every bin, so it's no great mental challenge to locate a part. And then all the similar parts are right next to it. I physically "shop" parts when I'm designing, especially things like connectors and cable ties and heat sinks. Simple things like 0603 caps I can shop on my computer; I know what they look like. Libraries stash books on shelves using an almost-as-good system. They don't randomly mix cookbooks with mysteries [1] with DVDs, and they do manage to keep the shelves in order. Books are worse, actually, because they don't get stored in bins, and can float between branches. >Why isn't your street address your name? Why do you want to force dogmatic catagorizations when practical things work better? We, engineering and production, designed and implemented this system together. We have *lots* of experience with stuff like this. We all love it. John [1] there are ambiguities, like the Nero Wolfe Cookbook. |