Why are networks so hard to build? (by alaric)

One of my sidelines is network management.

Often, the problem is this: you have a bunch of sites, each with zero or more external connections out to the wider Internet (or to people who you provide an Internet connection to), and each with zero or more computers that need some level of network connection (be they servers or workstations). Each computer needs to be able to talk to some subset of the other computers, and maybe able to talk to computers out on the Internet or some other external network, and maybe computers on the Internet or some other external network are able to talk to it. And computers may be on public IP addresses, or on a private IP address; in the latter case, if it can talk to other external networks there needs to have a public IP address (possibly shared with others) that its connections are NATed from, and if incoming connections are allowed, there must be a public IP to which those connections are sent to be "forwarded" into the private IP. We can think of those NAT/forwarding public IPs as "virtual IPs", which don't correspond to a physical computer, but seem to by way of some form of port/address translation.

Also, each computer or external network connection needs some level of reliability. Some have low requirements, and we can happily tolerate perhaps up to a day of outage per year; that's mere 99.7% uptime. The fabled "five nines uptime", 99.999%, equates to a maximum of about 30 minutes of downtime a year. And that downtime isn't just used up by equipment failures; if your network's requirements grow and you need to upgrade things to provide more capacity, you might need some downtime to replace and reconfigure things.

In other words, the problem domain is already complex. But the fun's just starting.

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Second Day of School (by sarah)

This morning Jean woke up and on finding out she was going to school again jumped out of bedding saying 'YAY! School!' I wonder how long this will last.

First Day of School (by sarah)

Effeciently or manically I went and bought all of Jean's uniform on Tuesday, then Sunday night once back from David's congrates party I labeled all the clothing with a fabric pen.

We were shock horror organised for her first day and woke up with plenty of time - I got her drink and snack ready.

I even put her hair up so it wouldn't get in her eyes!

She looks really cute and a lot older in her uniform even if the cardigan reaches down to her knees 🙂

And then we headed up the Hill.

Once at the playground she hovered nervously with us whilst a neighbour took our photo - the family all together 🙂

When the bell rang some preconditioning thing from Pre-school cut in and she automatically queued up the other children.

I did find it a bit tearful though I didn't actually cry - not really sure why but I sort of just stood there staring at the door when they'd all gone in.

She loved school and was excited to find out she would be going back again which was sweet 🙂

R7RS (by alaric)

There has been recent discussion on r6rs-discuss about the r7rs draft charters, most of it arguing from various camps.

I want a Scheme that lets me apply advanced programming language techniques - lightweight Higher-order functions and Hygienic macros rather than Boilerplate code, Continuations rather than a fixed set of predefined Control flow mechanisms, symbols rather than Enumerated types, Functional programming rather than getting tangled with too much state, dynamically-scoped parameters rather than God objects - to my day-to-day tasks. I'm a professional programmer; for a living, I've written code in Java, C, C++, PHP, Perl, Python, Ruby, SQL, AWK, shell and JavaScript, and I'd love to have been able to use Scheme for all of the above. I'm limited more by the usual commercial pressure than by any technical issues with Scheme or the qualities of my favourite implementation, Chicken, so my wishes for R7RS are relatively minor in terms of changing the semantics of the language. What I really want is a Scheme report that will unit the Scheme community, so we can continue to have a wide array of innovative implementations that all have their own strengths and weaknesses - but with much better portability of libraries between them, so they really do start to feel like one language with multiple implementations rather than separate languages.

So I feel that things like module systems and access to networking needs to be standardised, so each implementation doesn't gratuitously have their own syntax for doing the same thing. But these things need to be optional, so implementations are not constrained to be large in order to earn the name "R7RS Scheme".

So I thought I'd step up and propose a solution.

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Why C++ is not my favourite language (by alaric)

Yesterday, I had a discussion with somebody who's a big fan of C++. He spoke of C++ as letting you write high-level code (with smart pointers, exceptions, destructors and templates conspiring to smartly remove lots of the normal drudgework of C programming), while still being able to perform low-level memory access like C if you want to, and getting highly optimal code. He admits that C++ is complex and takes a lot of time to master, but that you can produce highly elegant and compact code once you've mastered it.

But I think this is broken.

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