Today we celebrated our college graduation. It was a pretty boring event with some pretty shoddy commencement speeches. Personally, it was something that I attended purely for my parents; I’d have loved to keep up my trend and boycott graduation ceremonies, but I got suckered into this one.

Photos are online. Enjoy.

The end is near…

Since Lina and I are seniors this year, we figured that we should go out with a bang and bring along two close friends for a cruise around the Caribbean. We took Royal Caribbean cruise lines to visit Aruba, Curaçao, St. Maarten, and St. Thomas, departing from San Juan, Puerto Rico. Needless to say, we had a blast!

I’m slowly making headway on it all, and should be caught up after next weekend. Needless to say, I have something to do besides falling asleep in my less intense classes.

To those who are expecting replies from me but have not yet gotten them: I will get around to you, I assure you.

At any rate, I was able to understand and write a concise proof for it, and have moved on to part two (of two) of the homework, which I have declared as completely impossible. Half credit never sounded better.

Aside from the fact that it’s a graduate-level course for which I do not have the number theory prerequisites, I again find myself in way over my head.

Getting help didn’t seem to help much with the second part of the homework — that is, proving one definition of the Carmichael function to be equivalent to another. The number theory expert here told me that “the Carmichael function is stupid.” Lately, I tend to agree. Needless to say, he didn’t provide much assistance in that area.

The aforementioned number theory expert, Keith Conrad, was immensely helpful in providing the background material for cryptography class that I did not previously have. Lina and I happened to run into him in an elevator, and he so graciously offered assistance during his office hours, despite the fact that we are not his students (nor will will ever be, assuming we are successful in avoiding any further math-centric endeavors).

It so happens that my professor in linear algebra is also a number theorist. Lina and I had an appointment with him scheduled for today, but unfortunately he had to cancel this morning.

Said cryptography assignment is due tomorrow during cryptography class at 15:30, including the generous extension given by the professor as requested. I’ll try to drop by the professor’s office tomorrow at some point before his class, but I don’t expect much out of it.

Wish me luck.

In good news, I should have more time to enjoy the things that I really, uh, enjoy. Such as… Not chemistry.

I plan to spend some time this weekend catching up on some of the FlipCount stuff I’ve been lagging pretty badly on. Throw in some shopping, Real Life™ work, and Gentoo work, and I think my weekend is fairly full already (really, there’s that much catch-up to do).

Next week should be even better, come Wednesday afternoon after my final exam. My plan? To relax. A lot. For a long time. Maybe I’ll go to the gym for four hours a day. Yeah, and code at my leisure for another four hours a day. And eat /sleep for the remaining hours in the day.

Ah, the life of a semi-free man. So close…

When I began looking at possible database schemas for storing NetFlow data in MySQL, I was worried about space. I was working under different assumptions back then (the numbers I had for data in was 1/100th what it is now), and I was thinking that perhaps I could keep the whole database under the 32-bit boundary (for old filesystems, portability, etc.). Now that the 2GB barrier is clearly broken with the sheer amount of data I’m dealing with, I’m not concerned at all with disk space – hard drives are cheap, or so says my boss. What does this mean for the schema? No more CPU-disk tradeoffs in favor of disk space. But does that also mean I can drop additional disk space, and a bit of CPU, for coding convenience, maintainability, extensibility, and ease of use?

In the short-term NetFlow tables, data lives for only a month or two at a time. Any more than that and insert times go down the drain — indices get too large for MySQL to cache adequately, even when there’s only two indices on the whole table. One of those indices is on a SMALLINT field (that’s a 16-bit integer for you non-MySQL types) corresponding to data in a SMALLINT-DATETIME lookup table.

Obviously there’s CPU overhead involved in converting the smallint back into a date, or vice versa, whenever the database is accessed. Furthermore, there’s a code inconvenience/overhead involved. Lastly, but certainly an important consideration, is that the system becomes less scalable: when places like NYU have the resources (such as a system with 32GB of RAM, like some of the Sun systems they’ve got there for network security) to keep a couple years’ worth or NetFlow data in MySQL, the system will break because 16-bit integers only allow for just over 1.8 years’ worth of 15-minute reports. Or consider an institution that wished to have more granular data, suppose 5- or 1-minute reports; not even considering the extensive code changes required to move from 15-minute granularity to some other level of granularity, the system comes crashing down in a mere 45 days. This is unacceptable. Even though my superiors at the workplace currently don’t intend on using on using the system in this way, chances are that their demands will change over the next year, and I want to be able to adapt the system to accommodate for those changes.

So now what I have a motivation for change, the question is on the direction in which to make the change. There are a few good options.

Bump the SMALLINT to a MEDIUMINT
Adding 8 bits would get me somewhere a lot more safe in terms of maximum capacity. But again we have the problem of scalability/maintainability if we want to change the granularity of the system. Also, like before, the system uses different date metrics for different tables, and things get confusing as well as difficult to maintain.

Drop the lookup table and move to DATE and TIME fields
Allright, it sounds a lot like overkill to store 48 bits where I could deal easily with 24. I’ll admit that. My logic is that since storage is no longer an object, things like this are possible. CPU-wise, I’m not sure exactly what the tradeoff will look like numerically; there should be a slight increase (okay, maybe not slight) in time taken to insert into the table because indices are larger, but total query time will be less because the number of queries is lower (no need for an extra lookup query on the date field). An added benefit, though, is that the entire backend could work under the same date metric. The huge plus here is that the system is completely scalable and 100% granularity-agnostic. Half minute, even ten second, reports? Sure, you got it. I can’t fathom needing anything less than one-minute reports, but I’m a stupid programmer/engineer, so I’ll quarter my minimum expectations and settle on 15-second reports as an absolute minimum (after which I would expect the system to just be real-time and not periodical in nature, which would require a restructure of the system anyhow).

I’m leaning towards the latter option above, but am open to suggestions and whatever my benchmarks report. I’ll make the final decision on this hopefully by the end of the day, definitely by the end of tomorrow.

1. Apple replaced the hard drive. Somewhat of a let-down, but I did have a backup of most everything I needed, so it’s not a huge loss. A blessing in disguise, actually: I’ve been meaning to reformat the machine and have a nice fresh clean start, I just hadn’t gotten around to it, and was kind-of waiting for Mac OS X Tiger to be released.
   

   
2. Apple managed to rip off one of the feet of my PowerBook, as per the pictures above. The first picture is what a normal ‘foot’ on a PowerBook looks like: a dark grey circular rubber pad mounted on a light gray circular piece of plastic. The second picture is what a missing ‘foot’ looks like: no dark grey circular rubber pad mounted atop a light gray circular piece of otherwise-very-empty-looking-not-to-mention-abrasive plastic.
3. Apple also managed to put some very light abrasions dead smack in the middle of my PowerBook’s LCD. To the untrained eye, they’re pretty invisible, but I can see them fairly clearly, especially when doing graphic design on a pixel-by-pixel level. The abrasions cover about a square inch of the screen and are shallow enough not to be noticeable to touch.

I called Apple’s support line immediately when I found out about (2) and (3) — which was when I got home that day after picking up the laptop from my local authorized service location. After a few minutes of hold time, another few minutes of talking to the lower-tier support dolts, and then yet another few minutes talking to a ’support specialist’, I had Apple’s rep apologizing to me and filling out a dispatch for a self-addressed prepaid-shipping box and packaging materials to be sent out to me. The support specialist said that she had put in the dispatch details that everything should be already paid for by Apple and there should be no cost to me at all. After a little bit of a fruitless run-around trying to get the dispatch to work through my local authorized service location rather than shipping directly to me (so as to shave off a day or two from the downtime I’d experience), I confirmed that I wanted the dispatch sent, and received the said materials in the mail two business days later.

As a side note, this may actually be another blessing in disguise: I do happen to have a dead pixel on my LCD and, while this is unacceptable to me, it is apparently acceptable to Apple — their LCD warrantee policy clearly states that an LCD with up to five dead pixels is ‘acceptable’. The Apple support specialist told me that they would have to replace my LCD. Also, seeing as how LCDs diminish in brightness with time, a new one might be a nice refresher for me and my laptop.

I plan on sending the laptop out on Monday in the hopes that I get it back sometime during that week — I’d really rather not be down over an entire weekend (these are the days I get the most work done).

The move is official, then. NIC is to be the production name of the Network Information Center we’ve been working on this semester. With any luck, NIC will hit the UConn Network this summer. Stay tuned for more – including Lina’s first post, coming tonight!

Joe, the Apple representative I spoke with at the Co-Op, seemed fairly confident that they would just replace the drive this time. On the service request that gets sent to the support tehcnician, Joe wrote, “The hard drive refuses to mount. Loud vibrations, akin to the blood curdling wail of a harpee, bring men to their knees.“.

Before doing all the paperwork with Joe, I asked if I might borrow a firewire cable and try to mount the drive on one of the machines there at the Co-Op, so as to perhaps salvage some of the data. It was a no-go. The drive wouldn’t even seek, and it made Disk Utility on the other computer go nuts. My last backup was a while back, too. Serves me right, I suppose. Let’s just say I’ll be e-mailing a few professors about the matter.

While the sounds emitted by the hard disk this time around were a bit worse than last time (there are scratching sounds to account for), I don’t think they’ll actually need to replace the drive. I guess we’ll find out on Thursday. Wish me luck.