# Posts by WhizzMan

6 posts • joined 11 Feb 2010

### How NOT to evaluate hard disk reliability: Backblaze vs world+dog

#### Basic calculations are sooo difficult

At 1.5% failure rate of drives you replace, you are looking at 1.5% of those 4 million dollars in replacement cost, plus the \$5000 for the guy replacing them. That's 65000 Dollars in total. If you want that back to 1% you are looking at 43333 in cost. The difference between those two scenarios is a bit over 21666 dollars in money you would save, if the purchase price of the drives was identical. On 30000 drives, you're looking at about 70 dollar cents more for the more reliable drives each to break even. Yes, they don't do warranty claims so each failing drive is a write off, they didn't put that in their cost model.

However, even at these numbers, this sort of maths doesn't fly. First, you need to have a guy available 24/7 to replace drives, or you need to invest in a lot more redundancy if you want them to only work office hours. That means investing probably double in the hardware, or you need four guys on shift duty, costing you 40000 dollar per month, if you take the 5000 for 2 weeks of one person's example given. You can't afford to lose data, so you need to keep on top of replacing drives, even if you have multiple copies of your customers data.

Second of all, you need to either invest well ahead in ample stock of drives, or take your chances on the market and buy whatever is available when you need new storage. Both options take a hit on the amount of money you are spending since either you have a cash flow problem and are buying devaluing drives without using them, or you're paying whatever price market demands at low numbers and whatever drive is available.

No nice large purchase discounts and having to buy more expensive drives if the cheapest ones are out of stock can easily set you back over 10% in purchase price and you have no full control over reliability of your systems. Buying large and not using devaluing drives will also cost you money since you can't invest it somewhere else and prices are dropping at a steady rate. No matter what you do, you're spending or saving way more money on stock control and operating costs than you would be on reliability of the individual drives. So yes, at this scale buying cheap and replacing more drives is the smartest option, but the calculations involved are a lot less extreme than 5000 vs. 4 million dollars as they suggest.

### Hate data fees but love your HD slab? Here's a better way to pay for bytes

Net Neutrality prohibits this and for a good reason. This way, providers would be in the business of selling movies to consumers and would have an unfair advantage to other parties selling the same movies on the internet.

The true solution would be to not have data plans but unlimited access, like in most countries with a truly competitive market. Carriers are carriers and should stick to that. Their business is to provide connectivity and not worry about what goes over that connection.

### Microsoft fattens Exchange Online mailboxes to 50GB

Double the price would not be wrong. Double the price of zero is still zero, after all.

### Gone

#### Critical Infrastructure

I've worked for several Critical Infrastructure customers in my career. Without exception, they all run Linux on the desktops that are used to manage the actual critical infrastructure. Being involved in both security and infrastructure administration, I can tell why they chose Linux.

1) Long term support. They all chose a distribution that would give their desktops an 8+ year life cycle. This was guaranteed at the moment they chose. Neither Windows nor OSX get promises like these at the launch of a new version.

1a) Portability; applications are usually easy to use on newer versions of linux. I've seen applications go for over 20 years. Both OSX and Windows don't have that track record. Granted, those applications came from UNIX, but still.

2) Customizability. Making an OS secure in the exact situation you are facing, requires good access "under the hood". Both OSX and Windows lack a lot here. They may have improved a lot, but they are still behind. Mind you, even if you have reasonable tools, it's still a highly specialized job and getting it right requires experts regardless of the OS you choose.

3) Designed as multi user, default deny, separate admin and user roles. Both Windows and OSX are designed for users first, then admin layers are added. Admin tools assume (partial) administration by the user. Because of the security model, there are large parts of Windows and OSX that are on "default allow" and only shielded by very thin security measures. This gives malware a big(ger) chance to break through on those than on (well implemented) Linux. For a critical infrastructure desktop you want something that just works and that is administered by people that are skilled admins and security experts, regardless of the OS.

Why not some form of BSD or Solaris? There is no commercial support for BSD easily available. If you want a vendor to support you because of hardware problems, you won't find hardware that will do so. Finding admins that are expert on both security and configuration of any of the BSD flavors will be difficult. This doesn't mean that some form of BSD isn't potentially as good as Linux, but that in practice, getting it up to that level is much harder for an organization. Getting Solaris supported is a pain and costs much more than Linux. The moment you run your own applications, all support is practically useless, so going that route is a dead end.

### The moment a computer crash nearly caused my car crash

#### Wrong diagnose

The symptoms (multiple occurrences of flapping speedo, stalling car, but no blocking wheels) and the multiple sensor error when read out, point to a totally different cause. One single occurrence of black ice will not trigger your speedo to go wild multiple times. There aren't multiple vibration sensors in any engine. There are knock sensors, that will help determine the optimal ignition timing, but those never trigger "errors".

If you have multiple errors on unrelated sensors and your dash behaving like a UFO just flew by, you have a bad ground problem. Either your engine or the ECU isn't grounded properly. That will make the ECU unable to read out sensors, drive actuators and it will "leak current" to everything attached, such as your speedo dial.

I'm predicting this will come back, because there is an intermittent grounding problem somewhere in your car. The guy in the garage can't even use his brain anymore and thinks the computer readout must be right and someone here blames it all on a software bug, instead of a simple hardware problem that has happened since cars had electrics built on them. Flaky light bulbs that only work if you whack on the fixture are common. If a car mechanic can't diagnose or fix a simple problem like that, he shouldn't be fixing cars for a living.

### Apple bets on Mac-only photo land grab with Aperture 3

#### I wouldn't be caught dead....

...editing photo's on the inferior TFTs apple puts in their portables. The horrible 15 bit displays that they insist on putting in to their top of the line laptops the last years can't make up for efficient software. If I have to take the stuff home to edit it on my Mac there, I'll never be able to do any pro work in the field with Apples kit, so I'm taking my chances running windows.