So, now they are encouraging addiction to high fat, high calorie diets. And, the reward is sitting back, watching a movie. Sounds like a great way to add inches to our kids waste lines. Just what we need in a nation plagued by obesity.
So, will we be able to sue them over our obesity in several years?
The grandparent got it correct. C does support multidimensional arrays. I suspect that C++ does too.
To validate, I pulled out my copy of K&R 2nd edition (Actually a copy I once rescued from a trash bin, and my copy is only "Based on Draft-Proposed ANSI C"). In section 5.9 Pointers vs. Multi-dimensional Arrays it points out,
Newcomers to C are sometimes confused about the difference between a two-dimensional array and an array of pointers, such as name in the example above. Given the definitions
int a[10][20]; int *b[10];
then a[3][4] and b[3][4] are both syntatctically legal references to a single int. But a is a true two-dimensional array: 200 int-sided locations have been set aside, and the conventional rectangular subscript calculation 20xrow+col is used to find the element a[row,col]. For b, however the definition only allocates 10 pointers and does not initialize them; initialization must be done explicitly, either statically or with code.
At work, my email was recently migrated to an exchange server. I use Evolution, so I figured that this would be a good chance to test its exchange capabilities (not that I have used Outlook much).
Initially, it didn't apply my filters to my new email There was no obvious way to modify server side filters from Evolution. No problem... I used Firefox to connect to the Exchange web interface, and logged in. Hmm... No way to modify server side filters. I called IT. They said "use IE".
I figure a way to fire up IE. It allows me to modify server side filters. I figured that I would translate my filters from Evolution to Exchange. I entered a rule based on a substring in the sender. That works for an application that sends me mail from different users -- all of which should end up in one special folder. No such luck. Exchange web interface requires that filters on senders require that the sender be in my address book.
In the end, I went from one simple rule based on a substring in the sender to several rules based on the subject line (and it still misses some cases). Sigh.
Magically, my evolution filters started working again. Go figure.
I have yet to find how to use Evolution to store files in Exchange (I think this is doable from within Outlook). There is no way to modify server side rules from Evolution. Evolution has support for Server side vacation mail.
Until about 2 years ago, it was getting increasingly difficult to find lego basic sets. In the last year or two, Lego has been releasing sets with lots of basic pieces -- plenty of standard bricks, and also windows, wheels, and other odd pieces that combine nicely.
My kids have lots of Legos. We additionally have some Megablocks, and one set of Tonka. The Legos stay together better than any of the other brands. For standard sized bricks I won't buy any brand but Lego. (For bigger blocks, Megablocks seems OK).
I suppose that I have been spending too much time watching videos with my kids, but this was done on The Magic School Bus over a decade ago. In this episode the schoolbus saves earth from an asteroid by moving the asteroid with a large mass.
It has the benefit of having many popular science fiction references.
Why isn't it a filesystem? Filesystems have been around since long before Posix.
A filesystem stores and retrieves files.
Here are some exmaples of filesystems that undoubtably violate posix:
FAT as shipped in DOS 1.0
Had no subdirectories
Had no notion of users
Had no permissions
Limited filenames to 8.3
CD-R
Doesn't allow data to be modified (or meta-data to be changed).
In addition, some filesystems allow remote access:
NFS
andrewfs
Coda
In addition, some OS'es allow some things to be treated as filesystems:
Linux has/proc filesystem - accessing in-memory data
Hurd allows filesystem access to tar files, and ftp servers
Why not sell the naming rights to your kids on Ebay? Perhaps it would help defray the cost of college, and councelling for being stuck with a name like "Grease Monkey Jones"
New: Magic-1 is now serving web pages using Adam Dunkel's uIP - click here
Magic-1 is a homebuilt minicomputer. It doesn't use an off-the-shelf microprocessor, but rather has a custom CPU made out of 74 Series TTL chips. Altogether there are more than 200 chips in Magic-1 connected together with thousands of individually wrapped wires. And, it works. Not only the hardware, but there's also a full ANSI C compiler for Magic-1 (retargeted LCC), and a rudimentary homebrew operating system. You can even telnet into Magic-1 and play Original Adventure.
This web site has served as the development repository for the project, and contains lots of pictures documenting the construction, as well as full documentation and diaries stretching back to the project's beginning in 2001. You can also find a few videos of Magic-1 running, including the first time it worked.
Start here, and then check out the Overview and Photo Gallery. To dig deeper, browse through Technical Info, Construction - and if you're really interested, you can even download Magic-1's full schematics.
Magic
In the summer of 1980 I celebrated my freshly minted B.S. in Journalism by blowing most of the cash I collected in graduation gifts on a TRS-80 Model 1 computer. Sitting on the floor of my apartment I fired it up, typed in the sample BASIC program and then "RUN".
WHAT IS YOUR NAME?
"BILL", I responded.
HI BILL
Wow! I was blown away. This was just a machine, but I could interact with it using language that we both understood. As a Liberal Arts graduate with next to no technical background, I found this completely astonishing. Over the next year, I continued to play with my TRS-80 Model 1 while working as a journalist on a small-town Kansas newspaper. I decided that I really wanted to learn more about how computers worked, so I went back to college and picked up a M.S. in Computer Science.
Now, more than 20 years later, I find myself with an urge to touch that magic again by building my own computer from scratch. By "scratch", I mean designing my own instruction set, wire-wrapping a CPU out of a pile of 74 series TTL devices and writing (or porting) my own assembler, compiler, linker, text editor and operating system.
I'm calling this computer the "Magic-1", or M-1 for short. It's a one-address, microprogrammed machine with one-byte opcodes. It features 8/16-bit data operations, functioning on an 8-bit wide data bus with 16-bit addresses (mapped via 2K-byte pages into a 22-bit physical address space). Code and data address spaces can be shared or disjoint, giving each process up to 128K bytes of addressing. User and supervisor modes exist, along with hardware address translation, memory-mapped IO, and support for DMA and externally-generated interrupts. As far as components go, it is built entirely out of 74LS and 74F-series TTL devices plus modern SRAM and old bi-polar PROMs for the microcode store. I designed it to run at 4 Mhz, but missed a couple of critical paths - so ended up at 3 Mhz.
Goals
OK, so I understand wanting to do your own CPU, buy why on earth are you doing it this way? I mean, why TTL - why not FPGA? And really, 16-bit virtual addresses in a 22-bit physical address space! What's the deal with that?
I guess any project should start off with some notion what of what you're trying to achieve. My high-level project goals are:
bullet
Touch the magic. By this I mean to gain a deeper understanding of how computers work, and specifically computers similar to those of the late 70's and early 80's that first fired my interest. For this reason, the Z80 loomed large in my mind throughout the design process, and running with an 8-bit data bus and 16-bit addresses just seemed right. Although I'm largely trying to use parts that would have been current in that time, I'm not shooting for historical accuracy. My choice of
Emacs and vi are both powerful editors. I have been using both on a daily basis for over 20 years (Yes, I used Gossling Emacs before Gnu Emacs existed). I used to program emacs (two different lisp flavors). I never learned all the availible lisp functions. I never learned all the key sequences of either vi or emacs.
The advantage of emacs mode over vi mode is that it is easier for most users to comprehend. In vi mode, users need to keep track of if they are in insert or edit mode. In emacs mode, they are always in insert mode (or search mode, but that it obvious from the screen).
Much of this works the same when using arrow keys, but in vi mode, it is difficult to get past the last character in a recalled line.
Secondly, the list of basic editting commands is a starting point. It lets the user start using the editor.
How many people really know and use all the vi commands? Knowing all the commands is not the point. Having an editing environment that makes the user efficient is what is important.
Hmm... Windows left me scratching my head about printers...
I have 2 printers connected to a W2K box - a laser printer, and an ink jet.
I recently got a laptop running XP. Initially it didn't notice my printers. The only way it would notice my printers is if I specified the windows path (\\machine\laserprinter). It required a name/password for the printer server!
Eventually, I installed the drivers on the laptop for the laser printer from original installation media.
I configured, and unconfigured the printer. Then, both printers showed up, and work correctly - even after logging out. XP no longer needs remote user ids.
What changed? Nothing that I can figure out. It just started working.
Some day I will understand Windows printing.
At least I can usually figure out Linux printing - but then I have been setting up printers under Unix/Linux for the past 18 years or more.
Last year, the AC died for one of my company's smaller labs. We connected some portable AC units, set up fans, removed the glass from a large window on this 10F day, and shut down about 1/2 the servers. This kept the lab temperature to about 95F. It was also a short term solution.
I work on kernel device drivers. Some functions assume that they are called with a lock held. Having an assert at the begining of this block of code adds a guarantee - if a new routine calls this function, it will fail if the lock is not held.
I use asserts to guarantee future maintenance won't break the code.
Linux will page and swap to swap files. Usually people use a partition for swap, but occasionally it is useful to add swap space via a file - such as when one is running low on swap.
Linux allows multiple swap files.
In the old days on Unix-like systems, it was necessary to have more swap than RAM - as each allocated page of RAM was also allocated a page of swap. That is on longer the case.
At my current job, on lab machines I usually have more RAM than disk space. If I alocate any swap space, I will allocate just 200-500MB. Many of the machines have 6GB RAM. I need to work to get those machines to swap.
I find Cosmic Encounter works best with 3-5 players. With 6 or more players it gets rather boring - especially if all one's powers are main player powers.
About a dozen years ago I played a game with at least 8 people (maybe there were 10 or 13, I can't really remember). Most of the game was spent waiting to be able to do anything (for a half hour at a time). Of course, that was with Matt's set - which started out as a regular set, before he added hundreds of powers, and cards, hazzards, and other non-standard elements.
My favorite never-ending game rule was played with a standard eon set (including all 9 expansion sets). I suggested power hour. We started with about 3 powers each. Each hour, on the hour, we each got an additional power. The longer the game continued, the more powers were in play that prolonged the game...
For many years I didn't play CE, but recently I played in another odd game - for extra-game reasons. One of the players was the son of the creator of the game. When there was a rules debate, he would call his dad to get a clarification. According to his dad, when plant plants Terrorist, he gets to create a list of bombs - so there are in affect 2 terrorists. Due to time constraints we used the house rule that plant gets to see the list of terrorist bombs, and if the last one explodes while plant is terrorist, he gets to create the new list.
It is rather coinsidental that this slashdot topic came up a week after I played CE for the first time in many years.
Slashdot Mirror
So, will we be able to sue them over our obesity in several years?
To validate, I pulled out my copy of K&R 2nd edition (Actually a copy I once rescued from a trash bin, and my copy is only "Based on Draft-Proposed ANSI C"). In section 5.9 Pointers vs. Multi-dimensional Arrays it points out,
At work, my email was recently migrated to an exchange server. I use Evolution, so I figured that this would be a good chance to test its exchange capabilities (not that I have used Outlook much).
Initially, it didn't apply my filters to my new email There was no obvious way to modify server side filters from Evolution. No problem... I used Firefox to connect to the Exchange web interface, and logged in. Hmm... No way to modify server side filters. I called IT. They said "use IE".
I figure a way to fire up IE. It allows me to modify server side filters. I figured that I would translate my filters from Evolution to Exchange. I entered a rule based on a substring in the sender. That works for an application that sends me mail from different users -- all of which should end up in one special folder. No such luck. Exchange web interface requires that filters on senders require that the sender be in my address book.
In the end, I went from one simple rule based on a substring in the sender to several rules based on the subject line (and it still misses some cases). Sigh.
Magically, my evolution filters started working again. Go figure.
I have yet to find how to use Evolution to store files in Exchange (I think this is doable from within Outlook).
There is no way to modify server side rules from Evolution.
Evolution has support for Server side vacation mail.
Until about 2 years ago, it was getting increasingly difficult to find lego basic sets.
In the last year or two, Lego has been releasing sets with lots of basic pieces -- plenty
of standard bricks, and also windows, wheels, and other odd pieces that combine nicely.
My kids have lots of Legos. We additionally have some Megablocks, and one set of Tonka.
The Legos stay together better than any of the other brands. For standard sized bricks I won't
buy any brand but Lego. (For bigger blocks, Megablocks seems OK).
Two of the reasons for a compensation package are to encourage employees to stay, and be productive.
It has the benefit of having many popular science fiction references.
Why isn't it a filesystem? Filesystems have been around since long before Posix.
/proc filesystem - accessing in-memory data
A filesystem stores and retrieves files.
Here are some exmaples of filesystems that undoubtably violate posix:
FAT as shipped in DOS 1.0
Had no subdirectories
Had no notion of users
Had no permissions
Limited filenames to 8.3
CD-R
Doesn't allow data to be modified (or meta-data to be changed).
In addition, some filesystems allow remote access:
NFS
andrewfs
Coda
In addition, some OS'es allow some things to be treated as filesystems:
Linux has
Hurd allows filesystem access to tar files, and ftp servers
So, why isn't it a filesystem?
Why not sell the naming rights to your kids on Ebay? Perhaps it would help defray the cost of college, and councelling for being stuck with a name like "Grease Monkey Jones"
Raid arrays should look like faster drives.
Back in the late 90's I did some work on the VMS TCPip stack. It was handy being able to uninstall the IP stack remotely over a DECnet connection.
Perhaps you are thinking of, To Serve Man.
Magic-1 is a homebuilt minicomputer. It doesn't use an off-the-shelf microprocessor, but rather has a custom CPU made out of 74 Series TTL chips. Altogether there are more than 200 chips in Magic-1 connected together with thousands of individually wrapped wires. And, it works. Not only the hardware, but there's also a full ANSI C compiler for Magic-1 (retargeted LCC), and a rudimentary homebrew operating system. You can even telnet into Magic-1 and play Original Adventure.
This web site has served as the development repository for the project, and contains lots of pictures documenting the construction, as well as full documentation and diaries stretching back to the project's beginning in 2001. You can also find a few videos of Magic-1 running, including the first time it worked.
Start here, and then check out the Overview and Photo Gallery. To dig deeper, browse through Technical Info, Construction - and if you're really interested, you can even download Magic-1's full schematics.
Magic
In the summer of 1980 I celebrated my freshly minted B.S. in Journalism by blowing most of the cash I collected in graduation gifts on a TRS-80 Model 1 computer. Sitting on the floor of my apartment I fired it up, typed in the sample BASIC program and then "RUN".
"BILL", I responded.
Wow! I was blown away. This was just a machine, but I could interact with it using language that we both understood. As a Liberal Arts graduate with next to no technical background, I found this completely astonishing. Over the next year, I continued to play with my TRS-80 Model 1 while working as a journalist on a small-town Kansas newspaper. I decided that I really wanted to learn more about how computers worked, so I went back to college and picked up a M.S. in Computer Science.
Now, more than 20 years later, I find myself with an urge to touch that magic again by building my own computer from scratch. By "scratch", I mean designing my own instruction set, wire-wrapping a CPU out of a pile of 74 series TTL devices and writing (or porting) my own assembler, compiler, linker, text editor and operating system.
I'm calling this computer the "Magic-1", or M-1 for short. It's a one-address, microprogrammed machine with one-byte opcodes. It features 8/16-bit data operations, functioning on an 8-bit wide data bus with 16-bit addresses (mapped via 2K-byte pages into a 22-bit physical address space). Code and data address spaces can be shared or disjoint, giving each process up to 128K bytes of addressing. User and supervisor modes exist, along with hardware address translation, memory-mapped IO, and support for DMA and externally-generated interrupts. As far as components go, it is built entirely out of 74LS and 74F-series TTL devices plus modern SRAM and old bi-polar PROMs for the microcode store. I designed it to run at 4 Mhz, but missed a couple of critical paths - so ended up at 3 Mhz. Goals
OK, so I understand wanting to do your own CPU, buy why on earth are you doing it this way? I mean, why TTL - why not FPGA? And really, 16-bit virtual addresses in a 22-bit physical address space! What's the deal with that?
I guess any project should start off with some notion what of what you're trying to achieve. My high-level project goals are: bullet
Touch the magic. By this I mean to gain a deeper understanding of how computers work, and specifically computers similar to those of the late 70's and early 80's that first fired my interest. For this reason, the Z80 loomed large in my mind throughout the design process, and running with an 8-bit data bus and 16-bit addresses just seemed right. Although I'm largely trying to use parts that would have been current in that time, I'm not shooting for historical accuracy. My choice of
To avoid the Slashdot pounding
I never see advertising on slashdot. Its a side effect of using adblock.
Emacs and vi are both powerful editors. I have been using both on a daily basis for over 20 years (Yes, I used Gossling Emacs before Gnu Emacs existed). I used to program emacs (two different lisp flavors). I never learned all the availible lisp functions. I never learned all the key sequences of either vi or emacs. The advantage of emacs mode over vi mode is that it is easier for most users to comprehend. In vi mode, users need to keep track of if they are in insert or edit mode. In emacs mode, they are always in insert mode (or search mode, but that it obvious from the screen). Much of this works the same when using arrow keys, but in vi mode, it is difficult to get past the last character in a recalled line. Secondly, the list of basic editting commands is a starting point. It lets the user start using the editor. How many people really know and use all the vi commands? Knowing all the commands is not the point. Having an editing environment that makes the user efficient is what is important.
Hmm... Windows left me scratching my head about printers...
I have 2 printers connected to a W2K box - a laser printer, and an ink jet.
I recently got a laptop running XP. Initially it didn't notice my printers. The only way it would notice my printers is if I specified the windows path (\\machine\laserprinter). It required a name/password for the printer server!
Eventually, I installed the drivers on the laptop for the laser printer from original installation media.
I configured, and unconfigured the printer. Then, both printers showed up, and work correctly - even after logging out. XP no longer needs remote user ids.
What changed? Nothing that I can figure out. It just started working.
Some day I will understand Windows printing.
At least I can usually figure out Linux printing - but then I have been setting up printers under Unix/Linux for the past 18 years or more.
Linus may return to the source control system he used before switching to BitKeeper.
If I remember correctly, he refused to use any source control system before agreeing to use BitKeeper.
Last year, the AC died for one of my company's smaller labs. We connected some portable AC units, set up fans, removed the glass from a large window on this 10F day, and shut down about 1/2 the servers. This kept the lab temperature to about 95F. It was also a short term solution.
Seems like the power source is the real problem. Perhaps you could fix that problem.
I work in sustaining, mainting Linux kernel drivers. Hopefully I get something to analyse (like a crash dump or other useful messages).
At least it isn't a hang, or a performance issue.
I work on kernel device drivers. Some functions assume that they are called with a lock held. Having an assert at the begining of this block of code adds a guarantee - if a new routine calls this function, it will fail if the lock is not held.
I use asserts to guarantee future maintenance won't break the code.
Studying distributed network algorithms accross wide area interconnected networks (though that is probably a CS persuit rather than an IT persuit).
Linux will page and swap to swap files. Usually people use a partition for swap, but occasionally it is useful to add swap space via a file - such as when one is running low on swap.
Linux allows multiple swap files.
In the old days on Unix-like systems, it was necessary to have more swap than RAM - as each allocated page of RAM was also allocated a page of swap. That is on longer the case.
At my current job, on lab machines I usually have more RAM than disk space. If I alocate any swap space, I will allocate just 200-500MB. Many of the machines have 6GB RAM. I need to work to get those machines to swap.
That's not exactly a bored game.
I find Cosmic Encounter works best with 3-5 players. With 6 or more players it gets rather boring - especially if all one's powers are main player powers.
About a dozen years ago I played a game with at least 8 people (maybe there were 10 or 13, I can't really remember). Most of the game was spent waiting to be able to do anything (for a half hour at a time). Of course, that was with Matt's set - which started out as a regular set, before he added hundreds of powers, and cards, hazzards, and other non-standard elements.
My favorite never-ending game rule was played with a standard eon set (including all 9 expansion sets). I suggested power hour. We started with about 3 powers each. Each hour, on the hour, we each got an additional power. The longer the game continued, the more powers were in play that prolonged the game...
For many years I didn't play CE, but recently I played in another odd game - for extra-game reasons. One of the players was the son of the creator of the game. When there was a rules debate, he would call his dad to get a clarification. According to his dad, when plant plants Terrorist, he gets to create a list of bombs - so there are in affect 2 terrorists. Due to time constraints we used the house rule that plant gets to see the list of terrorist bombs, and if the last one explodes while plant is terrorist, he gets to create the new list.
It is rather coinsidental that this slashdot topic came up a week after I played CE for the first time in many years.