Oracle's GPL Linux Firewire Clustering 168
Smoking writes "It seems that Oracle just released libraries to allow low cost Linux clustering solutions using firewire...
Aside from the coolness factor (imagine a beowulf cluster of DV cameras...) it's quite new for Oracle to release GPL software. They also seem to include really useful tools for NIC failover, Wizard building framework and integration of the cluster into Gnome (via a gnomevfs plugin)."
Thanks Oracle! (Score:5, Funny)
Thanks!
Re:Thanks Oracle! (Score:2, Insightful)
Cheap! (Score:5, Informative)
The Firewire cards needed to build a cluster can cost as little as 10% as much as the required FiberChannel hardware
Not to mention the FiberChannel switch. The Brocade [brocade.com] fiber switch we use to tie our three SGI Origins to our SAN's storage RAID was over CA$12K when we bought it.
Re:Cheap! (Score:3, Informative)
Not to mention the FiberChannel switch. The Brocade [brocade.com] fiber switch we use to tie our three SGI Origins to our SAN's storage RAID was over CA$12K when we bought it.
Yeah, but you only get 20% of the speed. Fibre Channel is at 2048Mbps now, compared to the 400Mbps of Firewire.
Re:Cheap! (Score:5, Interesting)
--
Evan
Re:Cheap! (Score:1)
You don't need the multiple thousand dollar switch to do Fibre Channel in a dual host configuration either. You can have a full working dual loop setup for under $2k+HBAs.
I am quite impressed with the total cost of this though. At $10/per Firewire card, you can have a setup to play with that is cheaper than just the cables in a shared SCSI cluster.
Re:Cheap! (Score:3, Interesting)
What's going on with firewire anyway - is there a bandwidth increase on the horizon? I tend to follow server hardware, and I know squat about firewire other than the three names and it supports 128 devices without having to have a central server a la USB. Is this is a solution that would be even more attractive when a higher capacity firewire rolls out in six months?
--
Evan
Re:Cheap! (Score:2, Informative)
Re:Cheap! (Score:2)
Re:Cheap! (Score:2)
s/1392/1394/g
Sorry about the brain fart.
Re:Cheap! (Score:5, Interesting)
My office-mate just spent a week attempting to configure a Brocade-switched Fibre Channel setup for HACMP. In his defense, it was his first attempt at such.
Everything I've ever heard about Fibre Channel reminds me of something Rube Goldberg threw together.
Re:Cheap! (Score:2, Funny)
dumbass (Score:1)
its not so funny anymore.
im hungry.
Re:Cheap! (Score:2)
Re:Cheap! (Score:3, Informative)
(For those not familiar with it, POOMA is a math library for C++ that handles multiprocessing in a very easy way. Debug it on a single processing system and run it on a multiprocessing system) It was developed at LANL but a lot of people use it. With FireWire2 and a bunch of cheap systems you could get a lot of supercomputer performance very cheaply.
Re:Cheap! (Score:2)
IEEE 1394b allows extensions to 800Mbit/sec., 1.6Gbit/sec. and 3.2Gbit/sec., all over copper wire. It supports long-distance transfers to 100 meters over a variety of media: CAT-5 unshielded cable at 100Mbit/sec., existing plastic optical fiber at 200Mbits/sec., next-generation plastic optical fiber at 400Mbit/sec. and 50-micron mulitmode glass optical fiber at up to 3.2Gbit/sec.
(Note, it supports all speeds over copper for normal cable lengths, the optical for higher speeds is only needed for runs up to 100 meters.)
Re:Cheap! (Score:1)
> they that can give up speed(fibre channel), to
> obtain ease of use (fibrewire), deserve neither
Hey! Nintendo uses firewire for the GameCube controllers and GBA links.
You try telling Godzilla 2000 (www.godzillaoncube.com) and King Ghidora that they don't deserve speed and ease of use! (If you have a death wish
Chief Tsujimori: "I won't let you get away. I will never let you escape."
Godzilla elegantly lifts his tail skyward to give her the "finger", crashes it down on the water, and submerges.
"Godzilla X Megagiras", 2000
Re:Cheap! (Score:3, Informative)
Not every application of fibre channel has to be complicated.
Usable? (Score:1)
I do wonder if a firewire cluster of high-end PCs will be any faster than one of it's components if it had an unshared, internal hard drive. Even if you have a bunch of old machines, it might be more tempting to buy a nice dual processor with tons of memory than spend more money buying firewire cards. Is firewire that fast that it's acceptable to use it for hard drive of the server big enough to need clustering?
Re:Usable? (Score:2)
So I'd say so, yes.
Re:Cheap! (Score:2, Funny)
The Brocade fiber switch we use to tie our three SGI Origins to our SAN's storage RAID was over CA$12K when we bought it.
12K Canadian? Whats that, $50 US
Kent
This comment officially sanctioned... (Score:5, Funny)
Re:This comment officially sanctioned... (Score:1)
We're busy computing.
Aliens found in last hour: 0."
Re:This comment officially sanctioned... (Score:1)
- taping the inhabitants of a girl's college changing room throwing hot grits at Natalie Portman.
Oh, the possibilities!Oh yea (Score:2, Funny)
Haha get it?! Because people are always like "imagine a Beowulf cluster..." so I said imagine a CLIC cluster! Haha! Genius!
Re:Oh yea (Score:1)
still wanna know how a CLIC (which is the new mandrake thing I think) works!
I had hoped the firewire was for net (Score:4, Interesting)
That would make it appear as a true parallel processing system and giving some API to take advantage of it. I guess something like that is still possible and with firewire being fast and cheap, it is something that may be worth looking in to.
-Tim
Firewire's future (Score:5, Insightful)
As firewire begins to scale to higher speeds this looks like an even better method to connect not only things like computers and their peripherals - but things like your television to your PVR to your camera to your computer.
So few new firewire products (Score:2)
I'd point out how unfriendly that is to us Mac users, but somehow, I don't think they care.
Re:So few new firewire products (Score:2)
Haven't seen any USB 2.0 ports on high end A/V equipment, either (eg DVRs). Seen FireWire ports, though.
Never seen anyone run IP-over-USB, but I have seen IP-over-FireWire. Kinda tricky connecting two computers with USB anyway, one end of the cable always seems to be wrong.
I'm not sure why anyone would want to run a keyboard/mouse bus at 480 Mbps, anyway.
(More seriously, I think there's just a general slowdown in introduction of new products because of the economy. I haven't noticed a particular difference in the number of firewire vs USB devices introduced.)
Re:So few new firewire products (Score:2)
I'm hoping firewire2 will be more successful, but I think USB might be too ubiquitous for it to get a strong foothold.
Out of the political loop (Score:1)
Re:Out of the political loop (Score:3, Informative)
1) It was designed by a competitor, Apple (who made the situation worse by implementing a high fee for a time). If it was designed by say, Microsoft or Dell, I doubt they would be working so hard to marginalize it.
2) It uses no CPU resources like USB. Greater tax on CPUs = need for better CPUs.
Intel would be well served to push IEEE-1394 (Firewire) as it encourages people to use their desktops for highly CPU intensive things like video editing.
Re:Firewire's future (Score:1)
http://www.intel.com/design/motherbd/bt2/index.
Re:Firewire's future (Score:5, Informative)
Re:Firewire's future (Score:3, Interesting)
It would be great if I could just simply plug my synth's into my network and assign ip's to them.
That way I wouldn't have to have a *separate* midi "network" and I would be able to use both my mac and my pc to make music without having to move my midi interfaces between the two.
And with gigabit ethernet availible, there's no problem with the bandwith being to small...
Also, you wouldn't have to connect everything *exactly* like before when moving them.
It really is hell to get everything back together in a working fashion when you've been out and about with your synth's...
Firewire isn't just for DV! (Score:5, Interesting)
This really is very cool stuff, and although I'm as suprised as everyone else about Oracle releasing open-source software (GPL nonetheless), it's another huge step forward.
Things like this piss off Microsoft to the Nth degree. That rocks!
Re:Firewire isn't just for DV! (Score:2)
if memory serves me correctly oracle announced a while back that it (the company) was going to be running on Linux starting this spring. It make a lot of sense to release the lib's to make it happen back to the community because now companies are more likely to be able to afford oracle software due to reduced licensing costs on Linux. thinking of FireWire only as a DV bus is like thinking of SCSI as only a scanner bus.
Survival Tactics (Score:5, Informative)
Actually, this is of no surprise to many that have followed Oracle over the past few years (perhaps 5+).
Oracle has been incoporating many open standards into their products recently which has been necessary to help keep the company in a (relatively) good position in the database server market. In the past all of their technologies were proprietary with their custom SQL extensions and their custom language for stored procedures and triggers (PL/SQL). Oh, and Linux - forget about it.
However much of that has changed and now they support Linux, XML, Java (I believe the first to have Java stored procedures), and a large portion of the J2EE platform with things like OC4J (their java app server based on Orion).
See these links for just a sampling of what I'm talking about.
Java Stuff [oracle.com]Linux Stuff [oracle.com]
Re:Survival Tactics (Score:2)
I guess that with a market share of 54% [oracle.com], "relatively" is the key word in that sentence...
Re:Survival Tactics (Score:4, Informative)
The Java stuff is cute, but by and large hasn't been implemented much. People buy Oracle because it's been around forever, and has been tested probably more than any other software on the planet. PL/SQL is still, by far and away, much more popular than their Java app. PL/SQL is incredibly optimized and solid, whereas their Java solutions are still getting there.
Their XML parser is definitely good, but the documentation for it is virtually nonexistent.
I don't think that they're necessarily adapting because they have to. Their core business is very strong. I think that they're just trying to expand their market. Of course, they've had lots of misses too. Some of their apps, like Oracle Forms (which is incredible) and their very nice web server while used, aern't nearly as popular as their core RDBMS.
And you forgot one of their coolest new technologies... OODBMS. Very bizarre. Very different. Hasn't taken off yet, but I've used it, and it's very very innovative.
Oracle's not in any trouble *yet*. But I think that they're hurt every time they try to work their way into the low end market to compete against things like MySQL. Bad idea.
Re:Survival Tactics (Score:4, Insightful)
that [neologic.com] innovative [adb.com], although I will agree that it is cool. I prefer PostgreSQL [postgresql.org] myself, but that's because I don't have tens of thousands of dollars to spend on all the commercial databases. *shrugs*
I apologise in advance if Oracle has redefined OODBMS to mean something different than I'm used to it meaning, but at least as much as I know what it is, it's hardly innovative. It's been around a very long time.
Re:Survival Tactics (Score:3, Informative)
Great, now I have to... (Score:2, Funny)
I wonder when Oracle is going to buy a company that produces firewire interface controllers... can you say instant SAN business?!?!
Just kidding, I think...
Hey you ! (Score:1, Funny)
That's not fair ! You just removed an opportunity for a +5 Funny comment !
(kidding. I know it would have been -1 Boring)
Red Hat to use Oracle's cluster software (Score:5, Interesting)
From article.
: Linux backers are working to strengthen the OS and bring it closer to competing with the proprietary versions of Unix that currently dominate the data center. Adding a clustered file system into Red Hat Linux is another step toward this larger goal.
hmm, not much there (Score:5, Interesting)
The (code not available) firewire stuff is a fix to allow sharing of firewrire disks. Which has been in the kernel for quite some time (perhaps they submitted it), but it is hardly radical (couple of lines of code, if your hardware happens to support it).
Seems more like a PR announcement to me.
Re:I was about to say... followup, real nfo (Score:1, Informative)
Shared Disk (Score:4, Interesting)
Does anyone know how firewire makes it any easier to share a hard disk between systems, for clustering support? According to the Oracle description of the patch "Firewire allows developers to easily and cheaply build a clustered system on a shared disk, which is useful for testing clustered applications...".
In a normal cluster configuration, SCSI provides an interface for allowing a hard disk to be shared between actual servers, so that if one goes down another can take ownership of the SCSI disk. Fibre is a common carrier, linking the computer systems to a disk array system (SCSI over Fiber), and Firewire could be used to replace it, but is the only benefit its expense?
Re:Shared Disk (Score:2)
Of those, "SCSI over IP" is very new and requires an expensive box that supports it (not to mention gigabit ethernet cards and switch). Fibre channel is pretty standard for large installs, but it's very costly abd SANs can be a real pain to setup. (I've done quite a few and would prefer to run screaming out of a room than do another with multiple vendors involved). Firwire is very easy to setup as long as you remember its limitations and very inexpensive. Consider that a 6 port firewire hub costs $99 at most (belkin.com) and firewire cards are at frys for $20. Add a few cables and a firewire drive and you're good to go.
I think the big point here is that you shouldn't design a large database for production on the current firewire, but you could economically setup dozens of these for testing and development. It may only be for their own cost savings. Can you imagine how much it costs Oracle to run dozens of test clusters on Sun or HP boxes? or even just the cost of fibre channel boxes and host adapters to hook up to cheap linux clusters?
Larry may have just saved himself a lot of $$$.
Just my opinion, I know nothing.
Re:Shared Disk (Score:2)
Of course, you probably don't want to have both computers mounting it as writeable simultaneously (kiss your filesystem goodbye), but that's a resolved issue.
Andyway, a suddenly-dead computer would appear to have just dropped off the bus (hotplug is part of the spec), so the the other could take over, just as with shared-SCSI.
Proper way to connect these (Score:4, Funny)
Firewire is not an alien technology (Score:4, Interesting)
Now is firewire had a liquid metal port that accepted any type of interface by morphing the connection, then firewire would be fucktacular! (Copyright 2003).
P.S. Starting throwing Copyright notifications on your posts, the "media" is starting to post OUR comments in their papers without our consent!
Firewire technology is important. (Score:5, Informative)
Firewire is hot-swappable. Try that with a external SCSI Drive. (not a hot swappable disk, the entire drive)
Firewire doesn't need a computer to work. USB 2.0 and 1.1 need a computer for it to work, but you can actually plug a DV camcorder straight into a digital VCR.
There is up to 50MB/s transfer rates (400Mbits/s) and the design is scalable, meaning the next iteration of Firewire will be 800Mbits/s, or possibly even 1.2Gbits/s
Ease of use: FireWire cables are a snap to
connectyou dont need device IDs, jumpers, DIP switches, screws, latches or
terminators.
Data and power: the FireWire cable carries data of course, but also power. I have one cable on my desktop for my iPod. It charges and synchs it to my iTunes with one wire. Serial doesn't do that.
USB 2.0 doesn't have real world speeds at the advertised 480MBs. Firewire does.
It is an industry standard. Bar none. Purchase a new digital 8 or mini DV camcorder. What do you get? A firewire port right on the side.
So basically, I wish all ports were designed with the expandibility of firewire in mind. I can do just about anything with it. Now even if I have a super-duper fast parallel port, there is tons of stuff I wouldn't want to do it with.
Re:Firewire technology is important. (Score:3, Insightful)
Well, technically an external SCSI drive can be hot swapped (I've done it), but having the bus idle while swapping is important. It's just not a good idea to yank out a drive when the bus is active. I haven't worked with true hot-swap drives; my hope is that they leave behind an intact bus when they are removed (otherwise, I guess hot-swap would be pretty moot).
Re:Firewire technology is important. (Score:2, Informative)
To be pedantic, "technically" an external SCSI drive cannot be hot-swapped -- the standard doesn't support it. It just happens to work most of the time, when, as you mentioned, the bus is idle. It works great, until it doesn't work (when you fry your SCSI interface).
Re:Firewire is not an alien technology (Score:3, Insightful)
The additional bandwidth itself brings versatility. Can you watch a movie, listen to Internet radio, or play a network game over a 9600 bps modem? Yes, technically. But you wouldn't, because it'd be painful.
Do you ohh and ahh over the fact you can hook up "almost anything" to a serial port?
No, because you can't. The classic serial port was already inappropriate for the bandwidth required of a printer, over ten years ago.
Re:Firewire is not an alien technology (Score:2)
It doesn't change its nature, in the limited sense that it's still just passing bits around. However, a serial cable is by application a phone modem cable, a download cable for PDAs, or a printer cable for a really low-end printer. A Firewire cable can be a real time digital video editing cable, an external hard drive cable, or a networking cable.
The fact that Firewire can transmit x bits per second is unimpressive. The fact that x bps means digital video is now possible on the desktop, on the other hand, is remarkable.
Re:Firewire is not an alien technology (Score:2, Insightful)
Take your car analogy, for example. Say you have a rusty Ford Pinto. You might be able to hit 60 MPH if you're lucky and have a tailwind, but it will get you from Point A to Point B (eventually). Later, you upgrade to a Dodge Viper. It's still a car, and will still get you from Point A to Point B, but the huge increase in speed (bandwidth) will most certainly change your driving habits. It will probably change your dating habits, too, if you're single. Not that a Firewire port will appeal to the ladies, of course, unless you use it creatively. With the ladies, it's not the size of the port, it's how you use it that matters.
With a Pinto, you have transportation, but you won't be allowed anywhere near the Autobahn. With a Viper, you can not only drive the Autobahn, you may even manage to pass a few cars. With the ability to move massive amounts of data hundreds of times more quickly than with a normal serial port, a Firewire port enables you to deal with data sets which heretofore would have been unrealistically big (such as full motion video, etc.) True, there will be (and are) technologies faster than Firewire, and when those technologies become accepted and affordable for the average user, Firewire will fall by the wayside, having served its purpose.
To say that bandwidth is irrelevant is the opposite of true. Bandwidth is speed. Everyone wants faster, bigger, better, for cheaper. Faster data links will enable portable devices to eventually hold far more information than they do now and transfer that information in less time. Being able to deal with increased information faster and more easily will enable us to use technologies in ways almost unimaginable now. What if our Palm Pilots had the same power and speed as a 1024-way SMP supercomputer? We could each do our own weather modeling, nuclear simulations, protein folding, or play a killer game of Quake 2^14 while checking our email and downloading the latest DVDs. Would you still want to hotsync over a 9600-baud serial port? I think not.
Re:Firewire is not an alien technology (Score:2)
Concerning your last parapgraph, "Everyone wants fasterm biggerm cheaper". Fine but you need to understand that there was little, if any innovation in firewire. It is still a serial communication that does nothing new that serial did. Firewire alone does NOTHING you've mentioned. The devices ATTACHED to firewire do. Case in point, palm pilots. Concerning the unrealistcally big data sets, bull. In a cluster environment you put 1 "PORT" interface in each machine in the cluster then pipe those connections to a multiplexer you get a ratio increase in bandwidth. I have a 2 year old USB multiplexer unit (now a door stop due to a power surge) that we had running in a MAN that pipped 41 USB channels for a proprietary communcation channel (do the math, and the 42nd connection was a control connection for a terminal).
There has been little innovation in computers in the last 10 years. Clusters are nothing more than the new version of mainframe, thin clients are an extension of the dumb terminal/main frame concept, KDE, Windows, Gnome, X Windows, etc are just new iterations of a really old interface that Xerox developed. Firewire is nothing new, just improved.
Think about it. YOu said your self, they are still cars in your example.
P.S. The Viper is not that good of a car, I'll take a 69 Mustang when cars were made of metal.
not correct! (Score:1)
Re:Firewire is not an alien technology (Score:2)
> starting to post OUR comments in their papers without our consent!
Copyright notices don't really do anything. Everything you write is automatically copyrighted by you. Furthermore, an explicit declaration of copyright already exists for everybody's comments. Read the bottom line of any Slashdot page:
BUS Limitations (Score:3, Interesting)
Could you connect a firewire card on AGP so that you can make use of the full 400 MBps that Firewire provides?
Re:BUS Limitations (Score:2)
Re:BUS Limitations (Score:2)
Re:BUS Limitations (Score:3, Insightful)
Re:BUS Limitations (Score:2)
Yet, PCI-X and infiband are a lot more expensive and not too much wider and faster then AGP 8X when sending.
IP over FireWire (Score:1)
-Max
Re:IP over FireWire (Score:2, Informative)
The speed of FireWire sure seems adequate to substitute some small network ethernet connections...
Google is your friend [google.com]
Re:IP over FireWire (Score:2, Informative)
Here's a page I googled. http://www.s.netic.de/gfiala/IP_over_1394.html
General Linux/1394 info can be found at http://www.linux1394.org/links.html
SCSI over IP over Firewire (Score:2)
Actually SCSI over IP sounds real good, but older SAN implementations used other, simpler, non-routable datagram based protocols to make things faster. The regulur SCSI over IP is TCP based.
Re:SCSI over IP over Firewire (Score:2)
of SCSI over SOAP over HTTP over TCP over IP over
SCSI?
Re:SCSI over IP over Firewire (Score:2)
Re:SCSI over IP over Firewire (Score:2)
Heh, there's also IP over SCSI [w3.ualg.pt] (see RFC-2143 [faqs.org]).
I guess if you're really perverse you could run SCSI over IP over SCSI over IP over
Re:SCSI over IP over Firewire (Score:2)
Under such circumstances, you could actually have SCSI over IP over SCSI - just so you can use a remotely attached disk!!!!!
Re:IP over FireWire (Score:2, Informative)
However, like it or not, direct link of 2 laptops with 400mbps firewire IS faster than 100mbit switched ethernet. I've copied gigabytes of movies from coworker PCs using firewire link, and if someone wanted to copy more than 2 or 3 movies while visiting our office, they would always bring a firewire cable or card, knowing how it would take much less time to transfer the data.
So don't bag something because you had a suckass experience with it on YOUR XP install.
.. they're also in cahoots with mysql (Score:3, Funny)
oh wait..
LINUX BOX as Firewire HD (Score:1, Interesting)
Have an old PII and a couple of IDE-RAID-Cards to build a TB Firewire HD.
Re:LINUX BOX as Firewire HD (Score:2)
Ahh but (Score:2)
Oracle is being a GOOD Open Source Participant (Score:5, Insightful)
Oracle has jumped 100% on the Linux bandwagon and is pushing it as the OS of choice for RAC (real application clusters) and claimed to switch all their internal production servers to Linux in the near future.
To see them giving code and "lessons learned" information back to the open source community is awesome. This is the type of business and open source relationship that proiveds a win, win for both the commercial party and the open source parties involved. Oracle benefits from a free and stable platform while contributing back to that community code that can help make the product (Linux is this case) better for everyone else.
Thanks Oracle, nice to see you doing a good thing for open source.
Re:Oracle is being a GOOD Open Source Participant (Score:2)
You forgot, "And get to jab Microsoft in the ribs at the same time."
MS Campaign backfired (Score:1)
Firewire for real clusters? I don't think so. (Score:5, Informative)
Then, I read some performance metrics on Firewire. High bandwidth. High latency [evaluation...eering.com]. Doh! The fairies stopped dancing for joy.
The problem is that in scientific computing, the time it takes for one node to say I need that data to another node, and actually get that data determines the performance of many more apps than does the speed of the CPUs.
So, until a cheap, low latency solution for communications comes by, real clusters will be communicating over Dolphin [dolphinics.com], Myrinet [myricom.com], or some other propietary technology [sgi.com].
Tony
Re:Firewire for real clusters? I don't think so. (Score:3, Informative)
Re:Firewire for real clusters? I don't think so. (Score:2)
What RAC uses the cluster interconnect for is cache fusion. If a data block is in the buffer cache of another RAC node, the local node will get it via the interconnect rather than from the disk. So we need many fast small transfers, rather than few large fast transfers. If the latency of the interconnect is greater than the latency of the storage array (which may be a massively cached EMC) then it's not worth it.
Re:Firewire for real clusters? I don't think so. (Score:2)
"proprietary" in the sense that they have no
meaningful competition.
Walmart read this (Score:2)
2 Firewire Controllers 100$
1 120GB Firewire Drive 280$
Cables and hubs 200$
Kick Ass Lindows Cluster 980$ PRICELESS
Clueless Ellison (Score:3, Funny)
Re:Clueless Ellison (Score:2)
GPL Nice... Registration bad. (Score:3, Troll)
Re:GPL Nice... Registration bad. (Score:4, Insightful)
Then why don't you mirror it so the rest of us can download (and subsequently mirror) it without having to register ? The GPL guarantees you that right. =)
Offtopic Question (Score:2)
Yes, those things are cool.
I'm not DB expert, so I'm curious:
What about this 10.7 desupport [com.com] problem?
Is Oracle being reasonable about the cost of supporting old software, or are they doing an MS-style push of their customers into an upgrade many feel they don't need?
As long as I can use one of these in my cluster... (Score:2)
The cost of Oracle.... ummmm nothing really! (Score:5, Informative)
Unless you are planning to use it in a commercial setting, Oracle is free as in beer!
The latest version of Oracle for Linux can be downloaded from here [oracle.com]
No TCP/IP support (Score:3, Informative)
great! (Score:3, Insightful)
Re:Why (Score:2)
My suspicion is that, in both cases, the answer is: they're not in as much demand as, say, Cat 5 Ethernet cables.
Re:Why (Score:2)
Re:Imagine... (Score:1)
Redundancy is good in networks, and bad in Slashdot posts