Re: What would be a truly relational operating system ?
Date: Thu, 12 Nov 2009 10:20:21 -0800 (PST)
On 11 nov, 05:39, paul c <toledobythe..._at_oohay.ac> wrote:
> Cimode wrote:
> > The current hypes about operating systems (Windows, Unix, Mac OS
> > Linux) gave to think about how RM main principles could be implemented
> > to extend the possibility of having a TRDBMS being implemented at a
> > lower physical layer (I mean on current disks, RAM, and CPU
> > architectures). That said, I am curious onto which prerequisites
> > should be respected on a lower level to respect independence between
> > the data layer and the physical layer when thinking of an operating
> > systel that would manage the relationship between thethe two layers.
> > I came up with the following ideas I would glad to exchange upon:
> >> The operating system should be IO relation-aware (for a lack of a better word) meaning that it should implement a physical storage mechanism that minimizes the number of logical operations required to represent a in memory relation and relation operation logical .
> >> The operating system should not be a direct image system, meaning that all information(files, file groups) should only be a result of a logical relation operation at runtime. As a consequence, the information can not be physically stored on an as-is basis. In other words, a traditional file would be a relation that would not exists before user interpretates it.
> >> The mechanism by which a file would be represented at runtime would be as a particular case of presentation of a relation, the same way an RTable could be one presentation.
> > Here are few ideas that came up but it brings other questions:
> >> Can current CPU architectures, RAM and disks adressing schemes sustain such model.
> >> What would be benefits ? The threats ?
> > Regards...
> No answers, just some probably rambling comments. I think these are
> really useful questions, maybe not for implementing a 'DBOS' but for
> appreciating the few things that a dbms really needs to do.
Thanks paul. One thing I appreciate about your feedbacks is that you seem to have an ability to intuitively guess the hidden intent. Limiting the implementation realm of RM to table based presentations is a clearly a limitation of its potential.
> Even if one
> thinks one knows them, they are easy to forget when one takes on a very
> ambitious task - in the last few days even the language experts on the
> TTM discussion list have gotten themselves tripped up over the
> difference between recording a function invocation and a function value,
> reminds me of the criticism I made here about confusing logical variable
> names with attribute values. Ideally, chief among the 'few things'
> would be figuring out how to make a typical physical machine look
Yes. And how to make the presentation layer more versatile. Both come hand in hand.
> One perhaps tangential problem is that mainstream OS designers aren't
> really into making coherent interfaces, let alone applying information
> theory, even though some of them jabber about that. There is a huge
> bio-feedback loop between the OS and HW designers and another one
> between the HW and compiler designers. Each group looks at what the
> other two did in the latest release and reacts to it. I guess there are
> three big loops altogether. To a big extent they are isolated from the
> rest of us, the loops create their own private logic. 'Good' marketeers
> understand this and know that they are not necessarily selling what's
> apropos rather what's available.
> Years ago, I had to cope with an IBM mainframe OS called MVS (a
> successor to the original 'OS/360' which many referred to as 'Obstacle
> System/360'). The vendor documentation was extremely uncoordinated,
> arcane, obtuse and never-ending. I thought the reasons were often
> deliberate. I didn't learn to make my way around MVS until I found a
> non-IBM book called 'Invitation to MVS'. This was a pretty short book
> while at the time IBM was said to be the second-largest publisher in the
> world, next to the USA government. It explained MVS in terms of the
> relationships between its key storage structures but didn't do much good
> since very few MVS users were aware of the book. But things have
> changed and today the desktop OS's are more complicated than MVS ever
> was (eg., it was designed to communicate with 'dumb' terminals and a
> very small selection of devices).
Yep. Good memories about JCL, object catalogs and IDCAM's come back...
> There have been similar though much thicker books about Unix but today
> it's ironic that even the Linux developers operate in just as adhoc a
> fashion as the others who have various corporate baggage on their backs,
> plus other insecurities. I guess part of the reason is that they have
> some baggage too in the form of Unix compatibility so technique
> impersonates real design. Of course the marketeers help confuse things
> with their doubletalk, 'baggage' doesn't sound so bad when you call it
> 'legacy'. It all reminds me of how a genome researcher I knew explained
> what he did: "It's a big race". In other words, nobody knows where
> they're really going. The lack of consistent lingo, also what Edward de
> Bono called 'porridge' words and the general decline in the ability to
> read critically is also a big impediment (not just in IT, the recent USA
> health-care debates show this - those against universal health care
> scare their constituents with TV ads' that talk of unrestricted cost
> increases, which is the basic problem with their private system in the
> first place!)
Well it is a shame that OS designers are most conservative than anybody.
> There have been a few embedded special-purpose OS's that had minimal
> (ie., only the essential) logical and coherent programmer interfaces.
> If I had to give the main design goal of an OS, that is it. But there
> is a big difference between an interface to hardware and an interface to
> a logical machine. Probably none of today's mainsteam OS's could adapt.
> Unix originally had what Fred Brooks called 'conceptual integrity' or
> suchlike with its file-stream metaphor but like the others you mention,
> it certainly doesn't have any comprehensive foundation theory akin to
> relational algebra and the emphasis remains physical, with lots of
> physical device library functions, each expressed in terms of the
> device's characteristics or the underlying machine language. In theory,
> such a base, if it existed, would offer similar advantages to a
> relational dbms, tight definition, logical rules for manipulation and
> therefore prediction and correctness proof.
Could you give me some pointers. As far as I know, logical storage mechanisms were never designed with the purpose of reducing runtime declarative representation of relations. IN order words ra never made it into storage physical data retrieval.
> Around the time Codd was writing his first papers, IBM had a project
> called 'Future System' which resulted in a scaled-down product called
> the System/38. It was only packaged as a mini-computer because the
> mainframe sales force was afraid a bigger one would cut into the large
> system sales that had better margins and bigger maintenance dollars. It
> had a linear address space, eg., you didn't have to cope with disk or
> memory architecture, and an abstract machine language but copped out
> with most of the same procedural application languages that the
> mainframes used. At one time, I was unknowingly in charge of a
> System/38 until one day the customer engineer showed up to look it over.
> Took an hour to find the room it was locked-up in. It was actually a
> development machine, but nothing ever went wrong with it! At the time,
> this was unheard of, even among the mini makers of the day, Dec, Prime,
> Data General and some others I forget. I think part of the reason was
> not to do with hardware, it was hard for application developers to bring
> things down. I remember working for a competitor where the doors were
> locked, not to keep secrets in, but to keep certain IBM materials out,
> for fear of lawsuits, but somebody sneaked some S/38 material in. The
> reason I mention S/38 is that I think the designers of it were hip to
> the idea of logical-physical separation even though IBM never tried to
> sell that idea.
I wish I had more material about S/38. Especially the math behind it.
> I'm probably an old-timer compared to most people in this group and
> remember having to squeeze IO support that worked fine on a 128K cpu
> into 16K. In those days IBM expected programmers to know and use disk
> architecture, it was called 'channel programming'. The channel was a
> mini-processor in its own right. Today even the software technocrats
> miss the point - it's laughable to me how much horsepower gets spent on
> off-base technique, eg., XML fans think the message is the medium,
> failing to understand that the key ingredient is compatible database
> definitions at the message ends, if they did then there would probably
> be only three kinds of messages between db's, eg., insert, delete,
> replace or maybe just assert and retract. Or maybe something totally
> declarative. I've mentioned here before how I think if today's memory
> space had been available thirty years ago, the database implementation
> field might be much different today, eg., there might be very little
> need for paging memory support in the typical OS that is concerned with
> database. One little craziness is the segment registers of the early
> Intel processors. At the time they were needed because of the small
> word size. Now that consumer cpus' have gigabyte and larger word sizes
> the OS people, eg., Windows, have hidden them from the application
> layer. This is a shame, because they have obvious uses for a dbms that
> can manage its own memory much better than an OS can. Meanwhile
> Intel/Wintel regularly add machine instructions to optimize graphics and
> The reason I mentioned messages has to do with implementation. Just for
> argument's sake, assuming one wants a 'DBOS' that uses today's hardware,
> the obvious bootstrap is to use existing hardware drivers, eg., to avoid
> all the bootstrapping work that Linus Torvalds had to do. Most people I
> know aren't aware that many drivers are proprietary, one of the
> semi-secrets of Windows commercial success. If somebody wanted to make
> a similar solitary effort, this might mean eschewing anything to do with
> Windows which might in turn mean avoiding, for example, graphical
> presentation functions so I'd think one really wants a very limited kind
> of OS, which means depending on more general OS'es on separate
> motherboards. Maybe paging support isn't needed, but I think the two
> main breakthroughs needed would involve a relational translation
> compiler and a database-to-database communication theory. The first
> matters if dependence on today's baggage-laden, bio-feedback driven ...
> plus de détails »
It is reasonnable to assume that not only a driver needs to be developped but also a filesystem that represents the relation. As the result of the last 10 years researchm I do have a promising filesystem but I am studying the opportunity of building on the top of a driver as opposed to the host OS.
Regards... Received on Thu Nov 12 2009 - 19:20:21 CET