Non Volatile Memories

 

Last Sunday I got a big scare - one of my newest external hard disk drives (HDD) let out a few scratchy noises and suddenly stopped working. Its LED light went out and the icon just disappeared from my desktop screen. Disbelief, panic!

I checked the plugs and ports, tried changing the USB port, tried restarting the system but the HDD just would not turn on. I had purchased this Seagate 2TB model just before Covid lockdowns! For a while, I just stared at the screen, shocked, confused, bewildered, wondering if I had just lost my collection of thousands of photographs, music, movies and other important documents.

Not sure of what to do next, iI checked for possible solutions online, hoping for some tips on how to resuscitate a cold metal box that held some of my prized collections and memories.

A YT video, "How Safe Is Your Data?" seemed like a good place to start. I was hoping to learn something reassuring from Christopher Barnatt, the acclaimed guru of Explaining Computers - on the lifespan of hard-drives, solid-state drives (SSDs), and other magnetic, solid-state and optical media. Far from being reassured, this video raised the panic levels!

Consider these facts presented by Barnatt -

• Magnetic tapes can last up to 30 years
• Most hard disk drives will last 3-7 years (!)
• SSDs depend on type of cells and number of re-writes, but should last 5-10 years. However if left un-powered for 1-2 years, data may be lost!

  In other works, as with everything else in life, nothing is permanent. More so in the world of charged electrons - a hard disk drive just wears out of spinning in circles; there is nothing solid about solid-state memory; Non Volatile Memory (NVMe) may be the latest thing when it comes to packing in superlative amounts of memory into tiny spaces but it is still volatile!

I have three HDDs - one each from Transcend, Western Digital, and Seagate. The oldest one is from Transcend and I had purchased it online in Japan in 2010 (15 years old!), and it stopped working last year. I tried accessing it from older laptops and Macs but it just refuses to show up on the desktop even after powering on.

So what is the solution? According to Barnatt, the most durable option (30+ years) is to burn all your important files into optical laser disks (high quality DVRs - read only). This however demands access to specialized equipment. Optical drives have all but disappeared from the new laptops. So the next best option could be to have multiple backups.

 As a first step I urgently needed a full backup of all my photos. Since the total size across HDDs came to around 750GB, I decided to try out the new kid on the block - NVMe SSDs. One thing I liked in particular about this option was that unlike traditional HDDs, you could order these à la carte. You could get the memory chips from the company you wanted (Samsung /WesternDigital / Crucial / Seagate), choose the capacity that I could afford (higher the better + you need to leave some space free for maintenance) and fit it into a a box enclosure of your choice.

So, after doing a bit of research and checking some options, this was my final configuration - 

• M.2 NVMe SSD enclosure from PI India (INR899) - comes with a GPT drive (GUID partition table), connecting cables (USB-C to C / USB 3.0), heat-sink sticker, pouch
• Gum-stick card - 2280 Western Digital/Sandisk Blue 580 M.2 NVMe 4gen (INR5399) -- a YT video from PI was useful for making sure it was fitted in properly
• Formatted on MacBook Air - exFAT (for MacOS+Win access) + GUID partition table (GPT seems more robust than MBR - master boot record) 

 So far the set up has been working beautifully. NVMe cards are so much more compact and seem sturdier than the clunky old HDDs! Now I hope the NVMe card will live up to its claim of being non-volatile.

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REFERENCES & LINKS

 
SSDs

• Explaining Computers (EC) - https://youtu.be/xA9Xq7hb6Q0
  
• M.2 SSD, PCIe adapters and USB enclosures - https://youtu.be/Ktqa11VT1xI (EC)
• SSD Life Expectancy - https://youtu.be/bv-IGhkcbP8
• M.2 NVMe Enclosures (desi gyan - BabaTech) - https://youtu.be/_huh7wb6Res - 
• How to Choose M.2 NVMe SSD - https://youtu.be/eGT-EIJNb_0 
• SD cards 2025 - EC - https://youtu.be/HtgIHfqQiC8
• SSDs - EC - https://youtu.be/F8k_XIEhKWo
• M.2 NVMe SSD explained (animated) - https://youtu.be/HvfIeTieXOI
• Wiki on M.2 SSD cards - https://en.wikipedia.org/wiki/M.2
  

• Partitions - GUID/GPT vs MasterBootRecord/MBR - https://www.howtogeek.com/193669/whats-the-difference-between-gpt-and-mbr-when-partitioning-a-drive

 

 

Solar Lighting a Dark Stairwell

How much does it take to set up a solar-powered system?

I've been mulling over the installation of a solar-based back-up for a while now. For starters, I wanted to install a self-contained system that automatically lights up our building stairwell. 

The problem is quite straightforward: We stay in an apartment complex that has about 30 towers (4x4 houses each), without a central power back-up. Each apartment has a stairwell that is vulnerable to power outages. At night - especially in winters - it becomes particularly difficult for the children and the elderly to use the staircases.

From whatever little I have gathered so far from the net, a solar-panel based lighting system would require: solar panels, a charge Controller, a deep discharge battery, wiring (4mm), a light-activated switch, and a panel of LED lights.

What I do not know for sure - and this is an ongoing challenge -  are questions for which I am yet to find dependable advise:

• How do I align the panels on the terrace so that they can be installed - and maintained -  easily?
• The most appropriate configuration of panel + controller + battery + LED panels?
• Which is a reliable place from where I can buy the components?

At least in NCR Delhi, it is difficult to find somebody who can guide you. The shopkeepers and aggregators always want to sell you the biggest system possible, whether you need it or not. They are all chasing contracts from big-ticket clients - the railways, public-sector companies, large housing complexes to keep the assembly lines running. Companies like Simpa Networks are building models that resemble telecom service providers. Not for them the one-time pocket-change from individual residences.

Reliability is also an issue. Almost none of the components comes with a performance guarantee. The usual refrain is "electronic cheez hai, kuch bhi ho sakta hai..." (its electronic stuff - anything can go wrong!). Not an encouraging start for people who see this as a long-term investment in clean energy.

Amongst all the people I have met, the most sensible advise came from a marketing executive at Maharshi Vedic Construction. His point was simple - longevity of any equipment depends on how you go about maintaining it. He gave the example of an inverter he has installed at home 17 years ago. According to him, regular vacuum cleaning and greasing is all it takes to make electrical equipment last longer. Clearly he had a point.

Yet, even as a manufacturer of solar panels and controllers, he could not offer a formal performance guarantee for the stuff he was selling. His panels cost INR40/Wa, so a 60Wa panel cost INR2400. The controllers were available only for 10A and 20A with a starting price of INR1100 (note: the 10A model came with a useful USB charging port).

Ultimately, I ended up buying the following stuff from the electonics wholesale market at Bhagirathi Palace, Old Delhi:

- Solar Panel Tata BP - 60Wa (INR 1200)

- Charge Controller - (INR 250)

- LED lights set - 12W (INR 150)

- Twilight Switch - 12V, 6A (INR 368) - from Electrocine Corp, 1801/5-6, Bhagirath Palace

- Copper wire (INR 160 for 10m - Kalinga Gold 4mm copper wire) 

- Battery - 26Ah, 12V

I was about to purchase a new 28Ah battery when a friend offered to pass on an old battery he was going to dump anyway. It has been purchased a year ago but seemed to have got completely discharged due to non-use. It took three about three days for the voltage to climb over 12V.

Apart from the battery glitch, the system seems to be working beautifully. 

Now, only a few questions remain: The battery runs out of juice in just four hours...is the LED panel drawing out more power than 12W? Or is it just an old, deep-discharged SMF battery acting up? How does one measure the W/h remaining in a battery unit?

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Vendor's Contacts:

* DC Twilight Switch - Electrocine Sales Corp, 1801/5-6 Electrical Market, Bhagirati Palace - www.escorp.in 

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LINKS & REFERENCES

* Bijli Bachao - solar panels in India - https://www.bijlibachao.com/solar/solar-panel-cell-cost-price-list-in-india.html

* Understanding Solar Power - an excellent resource that brings "Solar Power to Ordinary People"-- https://livingonsolarpower.wordpress.com/  

* Instructables - Solar charges with day-night switch - http://www.instructables.com/id/Solar-charger-with-day-night-switch-v2/

- 2N3904 NPN Transistor, linked to photo transistor and then using a 100k pot to regulate the sensitivity level.
- Day-night switch - http://www.ebay.in/itm/222242083233?aff_source=Sok-Goog
- INR 292 on EBay

- Solar charge controllers - https://www.batterystuff.com/solar-chargers/charge-controllers/