Windows and Linux are not the same

We like to think that operating systems are commodities, that Windows performs just as well as mac OS, and they both perform as well as Linux. I'm not sure about mac OS, but I can think of one significant difference between Windows and Linux, and that difference may affect the lifespan of the hardware.

Specifically, the difference in Windows and Linux may affect the hard disk drive, when it is an SSD (solid state disk). SSDs have a limited lifespan, in the number of reads and writes. This is important because Windows and Linux show different behavior with disk activity.

My experience is that Linux has minimal disk activity. Linux loads, creates a login session, does a few more things (I suspect that it runs 'apt' for an update) and then sits and waits. No disk activity.

Windows is quite different. It loads and creates a login session (just like Linux). But then it keeps doing things. Computers with disk activity lights show this activity. (Is Windows downloading updates from Microsoft servers? Checking for malware? I don't know. But it's doing something.) And it does this for at least 30 minutes.

That's before I log in to Windows, and before I launch any applications, or check my e-mail, or visit web sites.

After I log in, Windows does more. One can see the disk activity (on PCs that have status lights). When I check the CPU usage (as shown by Task Manager), I see lots of different tasks, many with vague names such as "Local Service".

Not all of this is caused by Microsoft. My work client has supplied a laptop that runs Splunk, McAfee, and a few other third-party applications (all installed by my client) and they wake up and do things every few minutes or so. All day long.

The immediate thought from this disk activity is: this cannot be good for SSDs. Each read operation and each write operation chips away at the lifespan of the SSD. (Old-style spinning hard disks are much less susceptible to this effect.)

The constant activity in Windows means that Windows will "consume" an SSD much quicker than Linux.

I certain that Microsoft is aware of this issue. I'm guessing that there is not much that they can do about it. Windows was designed to run lots of tasks on start-up, and throughout the day. (Also, it's not really Microsoft's problem. The fact that Windows "burns out" SSDs means that people will replace the disks, or possibly replace the whole PC. People will view this problem as a problem of hardware, not a problem with Windows.)

I tend to keep computers for a long time. For computers that run Windows, I look for systems that use the older hard disks and not SSDs. That's my strategy. Let's see how it works!

Servers need RAM-based SSDs, not flash-based SSDs

How to store data? How to store data on servers? In the "good old days" (prior to 2012), servers used spinning platters of metal (disk drives) to store data. The introduction of SSDs complicated the issue.

SSDs (solid state disks) eliminate the spinning metal platters and use semiconductors to store data. Today one can purchase an SSD that plugs into a PC or server and acts just like a hard disk.

SSDs provide faster read and write times, lower power consumption, and greater reliability (mostly -- more on that later). Their cost has been higher than hard disks, but that has changed. Prices for SSDs are now in the same range as "classic" hard drives.

But life with SSDs is not perfect. The solid-state disks use flash RAM, which allows data to be stored after the power is off (something we want in our storage), but flash-based RAM is not that durable. The heavy workload that servers put on their storage systems causes failures in SSDs.

I'm sure that many folks are working on methods to improve the reliability of flash-based RAM. But for servers, I think there may be another path: classic (that is, non-flash) RAM.

We've been building RAM for decades. We know how to make it, in large quantities, and reliably. Classic RAM is typically faster than flash-based RAM, and typically cheaper. So why not use it?

The big difference in classic RAM and flash-based RAM is that classic RAM, when you remove power, forgets everything. An SSD built with classic RAM would work beautifully -- until you powered the unit off. (And even then you would notice the problem only when you powered it back on.)

The impression is that such an arrangement would be useless. I'm not so sure, for two reasons.

First, while desktop PCs are powered on and off regularly, servers are not. Servers are typically installed in data centers and kept on, twenty-four hours a day, every day of the year. If the server stays on, the data stays in RAM, and everything works.

Second, it is possible to build classic RAM SSDs with small, auxiliary power supplies. These small power supplies (usually batteries) can keep the RAM active, and therefore keep the data, while main power is not available.

RAM storage units are not new. They date back to the mid-1970s, and have been used on IBM mainframes, minicomputers, and even Apple II computers.

I suspect that at some point, someone will figure out that classic RAM makes sense for servers, and build SSDs for servers. This will be another step in the divergence of desktop PCs and server computers.