Look up computer generated holography! It is certainly possible to calculate a hologram of a letter which focuses at some different depth than the screen.
There are issues which arise from restricting the hologram to a real valued grid, like limited FoV and noise, but these are not impossible problems to solve and existing technology is already quite good in terms of image quality.
Each of your two eyes only sees a 2d image, and your brain combining this information is what gives you depth. I'd say it's holographic in that each eye receives different information and you perceive depth when looking into it.
If you're asking whether you can see multiple translucent layers, like a hologram from a movie or tv show, then I'd also say yes. But I'd warn that there's a 58 degree viewing angle in front that you can see the images from. You can't look at the sides (or back!) of the display and see anything, for that matter.
VividQ | FPGA Engineer, Holographic Optical Engineer, Senior Software Developer, Senior Systems Administrator | Cambridge, UK | Full-time, onsite
VividQ is a VC-backed, deep tech software company with world-leading expertise in 3D holography: the next generation display technology. Our expert engineers, mathematicians and computer scientists out of the Universities of Cambridge, Oxford and St Andrews have solved key technology barriers in the adoption of holographic display for mass commercial application. VividQ powers devices developed by OEMs across the US, China and Japan, establishing a new standard of display.
I have noticed that Google Shopping is blocking results for "N95 mask" in the UK, making it more difficult to find retailers which sell them. On the other hand there are thousands upon thousands of results on eBay/Amazon, most of which cannot be trusted.
No idea how reliable they are, but that's always the danger when you buy anything from a small shop. I don't like the look of is as I can't find any corporate information about the store on their site, but it's no worse than buying anything else online.
Having recently acquired a NAS for use (among other things) as a single source of truth for photos spanning ~15 years, I have done a lot of research around backups.
These are the threats I have considered and would like to mitigate against, in no particular order:
1. Physical damage or theft to the NAS and supporting hardware (e.g. backup drives in my home).
2. Accidental deletion or corruption of files through user error.
3. Ransomware which targets my NAS. In particular a sophisticated malware author could target common cloud backup destinations by looking for credentials stored on the NAS, and delete any backups, although I have not heard of any such attacks in the wild.
The first threat seems simple enough to mitigate: make regular backups backed by cloud storage, and keep offline credentials for accessing the backup in multiple geographical locations as well as a cloud based password manager.
The second is also not troublesome: use a filesystem which supports versioning and take regular snapshots.
The third is where I have been somewhat disappointed by the options. An effective strategy is to keep an external hard drive which is plugged into the NAS regularly and keeps a clone of the data. However, an extremely cunning malware author could still pre-empt this by corrupting data on plugged in drives. This is extremely unlikely, but here's where I was hoping for better options in cloud backups: effectively all the pieces are in place for immutable backups, except for the tooling.
Options such as restic and rclone don't have good (if any) support for targets which support immutability, such as AWS S3 and BackBlaze B2. My current solution is to use a version of restic which I have patched to not require delete permissions when targeting B2, and very carefully manage API keys so that deleting backups would require compromising my BackBlaze account. In case a script does try to corrupt the backup repository, there are few if any supported ways of accessing a past version of a B2 bucket, although rclone comes very close and could support this very nicely with some minor tweaks to the B2 backend.
I will be keeping a close eye on this, and hopefully if I have the time I can make some PRs to push the open source tooling in this direction.
I am surprised you didn’t find security to be a key issue with network attached storage.
* Physical security. On 1, in case you have a synology NAS, it does not offer full disk encryption. Its folder encryption also has a number of problems. Your mitigation here (back ups) doesn’t help with loss of data to others.
* Network security. In addition to the physical security, consumer NAS devices don’t do enough in network security. Some of them come with closed source operating systems with a lot of potentially dangerous sharing and networking features. The code is often not reviewed.
On 2., you can use ZFS or btrfs, and they offer good features, but come with separate set of problems.
I spent some time on NAS security and couldn’t find a good solution. I thought I better let Amazon and google to secure my data.
Regarding comsumer NASs having poor security, I completely agree, however it wasn't too relevant to my personal threat model. Backups of my computers (which could potentially compromise credentials) are encrypted before they go on the NAS, and if I needed to sync anything sensitive it would be encrypted locally.
Using my NAS for sharing photos and files with family/friends opens up security holes that encryption at rest wouldn't help with, and I accept the tradeoff of potentially leaking data. What is less acceptable to me is any risk of data loss.
