Prices of SD card memory have fallen and capacities have increased, but read and write speeds can vary greatly, which ultimately impacts the performance of a Raspberry Pi, affecting how fast it boots up and loads programs as well as program performance.
The designers of Raspberry Pi are developing a new suite of tools to perform diagnostics on the Raspberry Pi. The first tool out is an SD card speed test app that helps users test the real speeds available on an SD card — and it gives them a weapon to combat shady vendors that make false read and write speed claims about a given card.
To install the SD card speed test, users need to type into the terminal "sudo apt update" followed by "sudo apt install agnostics".
After installation, users can access the new app "Raspberry Pi Diagnostics", featuring a simple screen that asks whether the user wants to run an SD card speed test. Users would check the "run test" box and then click on "Run Tests", which should take about a minute to complete on the Raspberry Pi 4.
Users are advised to run the speed test on newly-formatted SD cards because running it on one that's already stuffed with data will likely return results that aren't indicative of its potential speed once it's been erased and reformatted. The result is delivered as either a "Pass" or a "fail".
"The pass / fail criteria in this test assume a new (or at least freshly formatted) card; don't be alarmed if the write speed test fails when run on the SD card you've been using for six months! If you do notice your Raspberry Pi slowing down over time, it may be worth backing up your SD card using the SD Card Copier tool and reformatting it," explains Raspberry Pi senior principal software engineer Simon Long.
Raspberry Pi developers have also released a new imaging utility, dubbed Raspberry Pi Imager, for imaging a used microSD card with Raspbian and other OSes.
Gordon Hollingworth, director of software engineering cycles at Raspberry Pi Trading, admits that programming microSD cards has "always been a little bit tricky", which runs against its other efforts such as its GUI and setup wizard to make using and setting up the computer quick and simple.
"The main problem comes from the differences between the operating systems that people's main computers are likely to use: Windows, macOS, and Linux all use different methods of accessing the SD card, which doesn't help matters," he explains.
"And, for some new Raspberry Pi users, understanding where to find the latest up-to-date image and how to get it onto the microSD card can be a bit confusing, unless you've had prior experience with image-flashing tools such as Etcher."
The new microSD card imager is available for Windows, macOS and Ubuntu. The tool downloads a .JSON file from the Raspberry Pi website with a list of all up-to-date download options. After selecting an operating system, the tool then reads the correct file from the website and writes it to the SD card, meaning users no longer have to visit the website manually and write the file to a hard drive and from there write it to an SD card.