Roland's blog

Suppose for a moment that animals recognized the symbols we use for them. So, a "marshmallow peep" is a small duckling. A bear lollypop or candle could be viewed by other animals as a representation of their young.

We use such symbols because they are cute. Well human babies are cute too. Wouldn't it be cruel to make chocolate human babies? Would you eat that?

Sure, most animals don't recognize symbols we use for them today, but I think it's quite cruel to use images of animals in such way.

cd /var/log/apach2 && for f in `ls *.log`; do echo "" > $f; done

PBS showed a news item about an AIDS vaccine:

A combination of failed vaccines seems to have more of an effect that either vaccine: ALVAC and AIDSVAX.

From human trials: From 16,000 that were given the vaccine:

• Of 8,197 given the Vaccine: 51 got infected
• Of 8,197 NOTgiven the Vaccine: 74 got infected

Statistically this doesn't mean much if anything. Because this can be attributed to some random factor. 23 off 8000 is nothing.
But, if you cook the data right: 23/74 = 31%. So the report says: "Risk Down: 31.2%". Seriously? This is ridiculous.

Thread Questions (codereading.txt)

 

1. What happens to a thread when it exits (i.e., calls thread_exit())? What about when it sleeps?

 

• 3 comments
• Read more

I have to come up with a project idea for my knowledge representation class but I am not too sure about the topic. Here are some ideas from some brainstorming.

• TV show recommendation based upon viewing tendencies - as a media center plugin
• Smart panels for wordpress -- pulling in internal links to content from social mediums
• Recommend conference presentations based on one's publications/or selected categories

Question 1. Which register number is used for the stack pointer (sp) in OS/161?
Answer: 29
As described by ./kern/arch/mips/include/asmdefs.h:#define sp $29 /* stack pointer */

Question 2. What bus/busses does OS/161 support?
Answer: Only one LAMEbus
As described by ./kern/arch/mips/include/bus.h: * The only bus we support for MIPS is LAMEbus.

Question 3. What is the difference between splhigh and spl0?
While both functions modify the interrupt priority levele, splhigh blocks all interruots by
seting the priority level to the highest value, while spl0 unlocks all interrupts by setting
spl to the lowest value.
As described by ./kern/arch/mips/include/spl.h

Question 4. Why do we use typedefs like u_int32_t instead of simply saying "int"?
typedef allows us to use a different name for a native type, in this case u_int32_t for int.
However, the C standard doesn't specify what the size of int is, and sizeof(int) may change
from platform to platform. Using typedef we can use a header file to appropriately match
a data type name to the proper native data type, for instance u_int32_t to a 32 bit integer type,
thus avoiding replacing all occurrences of int in the source code if the application
is ported to a different platform.
Source: http://en.wikipedia.org/wiki/64-bit

Question 5. What does splx return?
splx returns the old priority level
As described in: ./kern/arch/mips/mips/spl.c

Question 6. What is the highest interrupt level?
Answer: 15
As defined in: ./kern/arch/mips/include/spl.h:#define SPL_HIGH 15

Question 7. How frequently are hardclock interrupts generated?
/* hardclocks per second */
#if OPT_SYNCHPROBS
/* Make synchronization more exciting :) */
#define HZ 10000
#else
/* More realistic value */
#define HZ 100
#endif

Depending on configuraiton, ie the value of OPT_SYNCHPROBS, the kernel generates hardclock
interrupts every 10000 or 100 times a second.

Trish playing fetch with Lily