Except that's always the case. You mean if Clojure crashes before it queues up 50 docs and sends them, the docs in the queue are lost.
Durability is a concern when it means the integrity of your data is unknown. You'd probably be doing something like this in a bulk load, in which case you'd know where it crashed.
If this were queuing and batching inserts from many users it might be more of an issue (a user thinks something happened and it didn't), but realize that the at a queue size of 50 this performs at about ~5500 inserts/second. (And you can reduce this queue size if you don't need to insert that fast) This would affect users who happen to make their request within a roughly 0.18 millisecond window. If confirmation is still absolutely important, the post also links a version at the end that -does- wait for and return the IDs of the inserted documents from couchdb, guaranteeing the inserts have happened, and it still performs quite well.
I had tried using SBCL to generate excutables before myself, using SDL as an external lib. Worked, but they were ENORMOUS (20mb). Not sure what I did wrong.
Actually AdBlock+'s element hiding rules can filter facebook ads. In fact I think a recent version has a subscription for filters that include facebook ad blocking.
I'm personally fresh out of high school, still 18 in fact. If your price point is so high that your target audience will actually -look- for a pirated version before they even consider a purchase, you are not going to have very good sales. The rule of thumb for DRM is pretty much if anyone can view the content, then the content can be cracked and distributed. Any significantly good, well-known product will be available for free somewhere, it's just a question of how hard it is to find.
Consider that many high school students can't purchase things online anyway, lacking credit cards, which means no matter what, "stealing" the product is more convenient for them.
If you use -any- sort of DRM, it will be extremely restrictive to the end user. Personally, I think really what is needed is for it to be convenient for the end user. This is what keeps me buying music from Amazon MP3. I don't even need any software other than a browser if I'm buying a single song. There's nothing to stop me from sharing my files with a few friends but Amazon MP3 probably makes up for whatever sales that would be lost this way because I like the service so much I recommend it to people all the time. Just give the user a raw, non-drm PDF file. If you really need to do -something-, dynamically insert a unique user ID on the last page of the book, just on the page, no steganography, write "Purchased by user #12345." PDF is pretty much a read-only format, so this wouldn't be easy to remove.
This probably won't keep people from casually sharing the book with their friends but will probably effectively put them off of sharing it publicly on the internet or p2p.
The thing is, greater anonymity via encryption etc. is not easy to use for the general public. Sure, you can hack around it but not everyone is a hacker. And of course, darknets etc. won't get around the Permission to Shut Down The Internet bit.
If you don't care about connection dropping, indeed just set up key authentication and run ssh in a loop as described above, instead of a complicated VPN, which will only really partially mitigate dropping of -forwarded- connections.
Secondly, you should be able to set scripts to trigger when a network interface comes up in most linux distros, but how to do it varies, for example /etc/network/ifup.d/ in ubuntu.
To fix constantly re-logging in to ssh:
- set up key authentication and run ssh user@host with your favorite parameters in a loop (shell script) so it reconnects when disconnected.
- in fact, have it run screen when connected, so you get right back to where you were effortlessy.
As for port forwarding, you will still be disconnected from everything on connectivity blips when ssh has to reconnect if you use ssh port forwarding. Try a VPN setup instead. You might have to fiddle with the host to keep it from sending RST's/FIN's as soon as you drop (though it shouldn't unless a packet for you comes in during the blip, I think). When you come back, if you come back soon enough, the connections should be restored without having been disconnected. (AS LONG as you have the same IP address on the VPN, so use a static IP setup)
Also, if you run your SSH -through- the VPN connection and recover quickly enough SSH shouldn't disconnect at all either.
More Edit: For long connectivity lapses (changing locations) all your TCP connections -will- drop. This is not something you can work around.
Certainly not the time to quit your day job and then try a start-up, but i don't see why you couldn't throw together your startup in your spare time. Is there a reason you need the 'time-consuming adventure' to actually consume so much time? It'll take longer to launch but on the whole, be less risky.
I think the sci-fi version of this in Doctorow's Down and Out in the Magic Kingdom is about the best -sounding- version of this sort of scheme.
You regularly make 'backups' of your brain and if you die your last 'backup' is loaded into a clone.
You (the new you) of course, don't remember anything that happened after your last backup. Made for an interesting plot device as well.
Durability is a concern when it means the integrity of your data is unknown. You'd probably be doing something like this in a bulk load, in which case you'd know where it crashed.
If this were queuing and batching inserts from many users it might be more of an issue (a user thinks something happened and it didn't), but realize that the at a queue size of 50 this performs at about ~5500 inserts/second. (And you can reduce this queue size if you don't need to insert that fast) This would affect users who happen to make their request within a roughly 0.18 millisecond window. If confirmation is still absolutely important, the post also links a version at the end that -does- wait for and return the IDs of the inserted documents from couchdb, guaranteeing the inserts have happened, and it still performs quite well.