What is a Public Cloud? Discover Top Rated Public Cloud Computing Providers, Services, Security & Technologies


The public cloud is what most people think of when they hear the term ‘cloud’. The public cloud simply means storage (or, less often, computing resources) provided by a third-party company that is accessed remotely. Organisations and individuals can upload their documents to the cloud over a regular internet connection, meaning that they don’t have to store them locally. Other models of cloud storage include the private cloud, which is similar to the public cloud except that the storage is held behind a company’s secure firewall and cannot be accessed by others, whereas the public cloud is typically used by many, many different customers, albeit with their own accounts. Another variation is the hybrid cloud, which combines elements of public and private cloud. The aim in this case is to access the benefits of both without their downsides.

Use of the public cloud brings a number of advantages. Chief amongst these is the ability to outsource the cost and inconvenience of storage. The cloud is also an easy way to back up data. It is popular amongst both individuals and organisations for that reason. However, there are also notable disadvantages. The nature of the services means that there may be security issues, known or unknown. When you send your data to a third party, you are trusting them to look after it. Loss, corruption, theft, tampering and unauthorised access are all possible – though there are various ways to address these issues.

Consumer Facing Public Cloud Companies

A number of large companies offer public cloud storage solutions, which is the most popular use for the cloud. Cloud storage is built into a range of applications and business models for the convenience it offers over local storage.

The companies that provide cloud storage each have a different approach and include cloud functionality for different purposes. The result is that their services may be limited or tailored to a particular offering. For example, whilst Dropbox is a platform that anyone can use, cheaply and easily, whilst Apple’s iCloud is integrated with its own ecosystem and is therefore of most help to those who already use Apple’s products. Microsoft and Google both offer cloud storage that is integrated with their office apps, but the approach is slightly different in each case – again making them suitable for different users.

When selecting a public cloud provider, various factors should therefore be taken into consideration, including:

  • The nature of the provider’s platform
  • Accessibility from other devices and platforms
  • Built-in functionality
  • Individual or organisational needs
  • Cost
  • Amount of storage
  • Security


  1. Amazon Cloud Drive

Amazon offers various cloud solutions, and its Cloud Drive is its preliminary answer to the likes of Google Drive and Microsoft’s OneDrive. Preliminary because it’s still early days for Amazon Cloud Drive, and it shows in the range of functionality that’s available. In the future they may offer more, but at this point the focus is on simplicity: it’s storage, without any bells and whistles. For example, unlike Google, Apple and Microsoft – other huge web companies – it hasn’t gone for any office-style apps or other integrated services. This is about no-frills storage. You’ll get 5 GB for free, but if you need more then you’ll pay $0.99 per month for 20 GB, which compares closely with Apple’s iCloud. On March 16, 2015, Amazon announced that $60 per year, will get UNLIMITED space.

The desktop app (PC and Mac) makes it easy to move files around between cloud and your native device, but on a smartphone it’s not up to much. It’s mainly designed for syncing photos, which it will do whenever there’s a wifi connection to save bandwidth you’re paying for on the phone. Another quirk is that you won’t be able to access office documents from their native apps on your phone or tablet, which isn’t particularly helpful. Ultimately, this is a good choice for photo and video backup, but if you’re looking for anything more wide-ranging, then it’s not the best option out there by a long chalk.



  1. Google Drive

It should come as no surprise that internet giant Google has pushed into the cloud storage space in a big way. The public cloud is, after all, a major part of its business. Gmail wouldn’t function without it – all those millions of email accounts need somewhere to store their billions of messages and attachments. Since the infrastructure was there anyway, it makes sense to capitalise on it, and that’s exactly what Google have done.

Google Drive began life as a few simple applications, but has evolved as other options have come onto the market and Google have realised there’s a profitable niche here. Along with a decent chunk of cloud storage to keep your docs on (15 GB), Google provide a whole office suite, complete with word processing, spreadsheets, presentation software.

Unlike Microsoft’s OneDrive, the office utilities are fully integrated into Google Drive. That is, rather than create documents and save them in the cloud, the apps run in the cloud to start with. There are strengths and weaknesses to this approach. The strengths are that you never have to worry about having the right software (it’s right there in the browser) or saving a document: everything is automatically backed up every few seconds. It’s also great for collaborating. Many different users can be given permission to read, comment on and edit a document, and it’s possible to work on the same file as others in real time. You can also use the Drive for regular files, that can just be uploaded rather than created in the cloud. If you upload office docs, you can convert them to Google Drive format and keep working on them that way. There’s also an app you can download to access your documents from your desktop. If you use Chromium, Google Drive is built in and it works seamlessly. For other OS’s, you’ll need native apps.

Against Google Drive, the software lacks the sophistication of a full Office Suite, though that’s hardly surprising. It’s good enough for casual work and great for collaboration, but don’t expect anything too fancy from it. You’ll need a Google account to access it, but since sign-up is free that’s no big deal. Of course, like the other big providers, this is part of an attempt to lock you into their interlinked services. It’s both a pro and a con that Google Drive is so well integrated with Gmail and all of Google’s other offerings.



  1. Microsoft OneDrive (previously SkyDrive)

OneDrive is Microsoft’s answer to the big storage providers like Google and Apple – huge corporations that build storage into their business model and incentivise (or require) customers to use it as a routine part of their services. Obviously, it doesn’t make much sense for Microsoft to sell their hugely successful Windows operating system, only to have customers go elsewhere for storage. That’s why they’ve built OneDrive into Windows 8 and up, fully integrating it into the user experience for Windows PCs, tablets and phones. If you have Windows 8+, you’ll see your OneDrive under the file explorer alongside other storage options such as your local hard drive. (Those with earlier versions of Windows or other operating systems can still use it by downloading an app.) It’s readily accessible from Microsoft Office, from which you can open and edit documents quickly and easily. Files are automatically organised by type.

One of the strengths of OneDrive – though some users might find this feature concerning – is that a your smartphone will upload photos to the cloud by default. Like other files on your OneDrive, you can then access them from any other compatible Windows device. It’s worth noting that OneDrive has an unusually stringent policy around content, particularly around nudity and pornography – though it’s unclear how strictly they enforce this.

OneDrive is a natural choice for anyone with a Windows device – in fact, because it’s built in, it encourages you to use other Windows devices. Microsoft is aiming for the same kind of monopoly over storage that Apple enjoys with its products. The downside is that it holds less appeal if you don’t use Windows. Although you can still download apps for other OS’s, it’s really at its best when it’s combined with Microsoft Office. That might not be a problem if you have an Android phone that you use to snap pictures and access them from a Windows PC, but if you use a Mac or Linux machine as your main computer then OneDrive suddenly loses a lot of its utility. The bottom line is, OneDrive is strongest when it’s used with Office functionality. Without that, it’s a very different proposition.




  1. Apple iCloud

Until relatively recently, Apple’s iCloud was reserved for Apple-only files. It was part of Apple’s proprietary set-up and was designed to support the Apple ecosystem. In October 2014 that changed somewhat, as Apple apparently saw the opportunities of opening its cloud offering to a broader market. Although it still underpins Apple’s core activities, you can now upload any file to the iCloud. As before, you can also access documents from a PC, as well as iOS devices. However, unlike the others options on this list, there’s no apps for Windows, Android or Blackberry phones, which still points firmly in the direction of Apple wanting to bring in more Apple users and keep them there, rather than allowing people to mix-and-match their devices, as most of the others have approached the issue.

iCloud will backup photos taken on an iOS device, and lots of other apps are iCloud-enabled, too. Auto-backup lets you copy your iPad or iPhone data to the cloud, so you can retrieve it later if you need to (in the event your device is lost or damaged, for example). Because it’s designed to work with iTunes, iCloud will allow you to download tracks to your library from any device. Your Safari bookmarks are also visible on different devices.

Apple have taken a step in the direction of Google by creating reasonably decent office applications that you can use on different devices; like Google Drive, they’re a little limited compared to their fully-fledged desktop office suite equivalents, but they’re not bad for getting started.

You’ll start off with 5 GB free space, but this isn’t really enough if you need to back up your devices or have a large number of photos. (Purchased tracks don’t count.) If you run out, you’ll need to start paying for more storage. 20 GB costs $0.99 per month, which should be enough for most users, but if you need to you can go all the way up to 1 TB for $19.99.

The iCloud is one of those options that makes sense if you’re already tied into the Apple ecosystem. If you’re not, then it’s not as convenient or seamless to use, and you’ll struggle with particular devices – in which case, it’s almost certainly worth going elsewhere.


  1. Dropbox

Dropbox is another extremely well-known name in the cloud storage world. Unlike some of the other players in the space, it’s platform-agnostic, so it works equally well regardless of whether you’re using Windows, Linux, Android, iOS, and so on. You can upload and access files either through the website, or by downloading an app to your native device. The apps link with your file system, so you can easily move documents around and shift them to and fro between the cloud and your computer.

One of Dropbox’s major attractions – other than its ability to play nicely with everyone – is its straightforward, clean, elegant design. It’s a simple system and that simplicity is what draws so many users to it. It has its issues, though. Depending on what you want to use it for, you may find Dropbox’s simplicity actually comes across as inflexibility and a lack of sophistication. Nevertheless, it’s easy to use and navigate, and that’s a powerful selling point if you just want to drag-and-drop files and let it do its thing.

When you first sign up, you’ll be limited to 2 GB of storage – which won’t be nearly enough if you want to back up lots of photos or media. There are lots of ways you can get more space, though, with a series of incentives. For example, there’s an auto-upload feature for photos on Dropbox’s mobile apps: activate this and you’ll receive an extra 3 GB. (You may, of course, be wary about enabling that kind of function – a number of recent stories of cloud hacks have made people cautious about uploading everything without checking, first, and prompted renewed interest in security issues.) You will also receive additional space for referrals – get a friend to sign up and you’ll be given another 500 MB, up to a maximum of 16 GB.

Ultimately, Dropbox is nothing too flashy – and that’s as much an advantage as a disadvantage. It offers a clean, simple user interface. You can upload any file you like. It works just as well on any system. If you’re looking for a straightforward cloud solution whatever device you use, this is a strong contender for starting out.


  1. Box

Box is similar in principle to Dropbox. It offers storage for all different file types, without the built-in tools or integrated applications offered by the likes of Google or Microsoft (though it is possible to create simple text documents). Like Dropbox, it has a web interface that’s platform-agnostic, so you can access it from any device. You can also download an app to move files between your desktop and cloud storage seamlessly.

Where it differs is its intended userbase. Anyone can sign up for an account, but Box is targeted more at the business community than individual users. (Although Dropbox is used by businesses, it is conversely more appealing for personal users due to its simplicity.) Box is somewhat more complicated, reflecting the range of purposes to which its users might want to put it. It’s not a full-on project management tool – there are other sites that deal with that pretty well – but Box does allow you to assign tasks to different users, change privacy permissions so that certain people can view and edit given files and folders, leave comments and receive notifications when someone leaves you a comment on one of your files. There’s a strong emphasis on privacy, so you can even password-protect documents and set expiry dates so that once a project is finished, given users won’t be able to access a folder any more.

Box’s strength is its suitability for business use, where all the privacy and sharing settings come into their own. These will not be of interest to most personal users, and can get in the way – they represent a needless complication for casual users, and if you just want basic storage then you’re better off with another option like Dropbox. On the other hand, if you’re looking for a business solution then you’ll likely find that Dropbox is too inflexible to meet the needs of all but the simplest tasks. Something like Box is far better tailored to the requirements of teams working together on a project.


  1. Spideroak

This is public cloud storage with a difference. Spideroak’s unique selling point is its security, and it goes about it in a very reassuring way. Every one of the major players out there works the same way: you upload your documents to the cloud and – if they are going to be encrypted – they are encrypted on the provider’s server. Naturally this has some drawbacks, as a number of extremely high-profile hacks has demonstrated.

Spideroak uses client-side, not server-side encryption. You start by downloading the app (Windows, Mac and Linux versions available). You documents are encrypted on your local machine, before they are uploaded to the cloud. This is a huge improvement on the traditional approach. It means that the provider has no access to your documents in their unencrypted form, because the keys are owned only by you. Rather than hoping that employees won’t view your files, you ensure that they can’t. Incidentally, it also makes it an awful lot harder for other parties to look inside your public cloud folder – whether those parties are government agencies or lone hackers. You start with just 2 GB of free storage, though there are various free upgrades available for referrals and so on.

Spideroak’s interface is pretty simple, roughly along the same lines as Dropbox. It’s not designed to do a lot more than store documents, and it wouldn’t make a lot of sense to try. For example, there’s no point adding tools like an office suite if the documents you’re uploading are already encrypted. Spideroak is intended to be used as a safe repository, not a cloud productivity suite like Google Drive. You can share encrypted files with trusted parties, but you won’t be able to collaborate on documents in the same easy way that you can with other options.

B2B and Enterprise Public Cloud Companies



VMware offer public, private and hybrid clouds, each of which will be suitable for different applications. Their public cloud offering has the advantage that you won’t need to re-architect to use it. VMware’s cloud is designed to allow your business to run both new and legacy applications in the cloud, so you can continue to use your existing software whilst accessing the benefits the public cloud has to offer. (Additionally, if your current infrastructure is built on the VMware platform, you can seamlessly extend to a hybrid cloud model.)

VMware’s Software-defined data centre (SDDC) approach allows businesses to combine agility and security, giving them the flexibility to build out a public, private or hybrid cloud as required. VMware boasts best-in-class service and support – one of the things that differentiates them from large off-the-peg public cloud providers, who generally supply the service but little else. Their integrated approach means that support is available across the range of services, through the same number.

VMware’s vCloud approach can be used as a complete computing platform as well as for storage. Storage options are On Demand and by Subscription. On Demand is a pay-as-you-go service that scales as you need it, though this flexibility comes at a slightly greater expense. Charges are by the hour for computing power, storage and additional services. It starts at $0.08 per hour for the most basic computing package. Storage starts at 20 GB SSD at $0.004 per hour. The Subscription service is a series of pre-bundled offerings that will be most economic for organisations that know their requirements in advance.



Cisco aims for a high degree of flexibility in their public cloud offering to enable customers to choose the best package for their needs. Last year, in response to growing competition and criticism of its proprietary and more expensive model, Cisco announced a series of new partnerships with Red Hat: moving to the open source OpenStack cloud platform; its Application Centric Infrastructure (ACI); and the ‘Intercloud,’ which Cisco describes as a network or cloud of clouds. The Intercloud brings together a wide range of providers with the intention of improving accessibility, lowering costs and maintaining security.

Cisco also offer a public cloud for cloud providers. This is based on the same open architecture and allows customers to take advantages of software-defined networking.



Rackspace is a well-known and trusted name amongst cloud providers, with more than 300,000 business customers in over 120 different countries. They offer a ‘managed cloud’ package that goes well beyond infrastructure alone.

Unlike other cloud providers, Rackspace offer only managed cloud, with three different service levels according to organisations’ needs. If you are confident managing your own platform and are only looking for the infrastructure, this means Rackspace almost certainly isn’t the company for you. On the other hand, if you don’t have the staffing or expertise in-house, Rackspace’s managed cloud is an attractive solution.

Rackspace’s packages start at $0.005 per GB per hour, for a minimum of $50 per month. This is the basic Managed Infrastructure package, which includes architecture and security guidance, code development assistance, and launch managers. Cloud Engineers are available 24/7 to help with any problems you encounter. As a relatively simple offering, this will give you a degree of latitude to take your own approach, with the support on hand as a reassurance if you have difficulties. If you are sure you won’t need these or have that knowledge within your organisation, you can get the same storage more cheaply elsewhere.

The Managed Operations (SysOps) package is a significant step up at $0.02 per GB per hour, with a minimum of $500 per month. This includes the basic support and set-up of Managed Infrastructure, but with much more to add value. You will be given assistance with day-to-day operations of your cloud workloads (infrastructure monitoring, OS maintenance/patching, and application maintenance). You will be supported by a dedicated account team, so you will have continuity across your dealings with the company and will be in touch with someone who knows your business and IT needs throughout.

The most comprehensive package is Managed Operations (DevOps Automation), which comes at a minimum of $2,500 per month. This is designed to facilitate development operations for your organisation. Rackspace will create your infrastructure at the software level and take care of configuration management for you. This involves Rackspace working closely with your own developers to assist your operation and reduce your time to market. The emphasis is on freeing you up to concentrate on your application, rather than spending time overseeing the infrastructure and applications you need to do your work.



IBM offer a broad suite of resources to help get enterprises up and running in the cloud. There’s an emphasis on business application rather than personal use, as you might expect from an organisation that started out as a provider of mainframe computers in the 1950s, when the landscape was very different. Now, they are still catering to the business community but with an updated set of resources aimed firmly at the 21st century. They even started offering a Big Data Analytics Software Solution. Their SmartCloud offering starts with three off-the-peg packages, but can be tailored with further services if required.

The ‘Social’ package includes collaboration tools like a personal dashboard, file-sharing capability, communities and instant messaging. These are common to all packages. There is also a mobile app for accessing files and chatting with your contacts – and again, cross-device capability is included as standard. You also get 1 TB storage, 50 GB Communities storage, and 5 GB wiki storage.

The ‘best value’ S1 package adds further functionality, including web meetings for up to 200 participants, plus email and calendar. Document editors allow collaborative authoring of files and on top of the storage offered by Social, you receive 50 GB SmartCloud Notes mail storage. Unlimited guest access is also provided. Mobile apps enable access to files, participation in online meetings, and synching email/calendar. S2 is a slimmed down version of this package, without the mailbox storage and document editors. There are also a series of standalone add-ons, such as synchronisation with Blackberry devices and archiving.



EMC’s VSPEX offers a ‘converged’ approach that places all of your infrastructure – computing, storage, networking and management – under the same roof. VSPEX is a portfolio of solutions, designed to give businesses choice in what they use for large applications. The VSPEX Blue package is designed for medium-sized applications, and aspires to simplicity across the board of installation, management and scaling. It’s intended to enable roll-out of VMs within 15 minutes of powering on.

There is a broad range of sub-options, with a series of products for enhancing performance for given application suites (Oracle environments, Microsoft products, etc). Private and hybrid cloud options exist. The End User Computing solution enables complete virtualisation of the desktop infrastructure, enabling fast and flexible deployment and eliminating planning and configuration issues. Virtual desktops can be deployed quickly and simply, whilst enabling central management, update and protection of virtual desktop infrastructure. This means client issues are addressed at the data centre, boosting productivity and reducing support costs.


HP Cloud

HP’s ‘enterprise grade’ Helion public cloud is based on OpenStack technology – an open source platform, in contrast to many of the proprietary ones on offer. It’s designed as a transparent public cloud that addresses business needs in the round. Computing, storage and platform are provided on with a pay-as-you-go or on-demand basis. There’s a free 90-day trial on offer, with XS instance and 250 GB storage (or just 500 GB storage), with no vendor lock-in and 24/7 support.

Pricing comes in 8 different tiers, starting at the most basic level of Cloud Compute. HP’s commitment to openness is clear from their pricing structures; Cloud Compute is charged on an hour-by-hour basis, with no minimum charges, no account charges and no lock-in period: it really is pay-as-you-go. The cheapest Standard Extra Small package offers 1 HP Cloud Compute unit, 1 virtual core, 1 GB RAM, and 10 GB of storage. This is priced at $0.03 per hour (Linux) or $0.06 per hour (Windows or SUSE). The scale of options goes up to Standard 8XL with 103 Cloud Compute units, 16 virtual cores, 120 GB RAM and 1770 GB storage, at $3.24 per hour (Linux), $3.57 per hour (Windows) or $3.40 per hour (SUSE). High-memory instances are available. To stop hourly charges you must de-allocate your instance; so long as your instance is allocated, no one else can use it – even when the instance is not running.

Block Storage starts at $0.10 per GB/month, and $0.10 per million I/O requests. A series of other add-ons are available, such as cloud DNS ($0.35 per domain per month – pro-rated to part-months). Other strands include Relational Database (1 GB RAM, 15 GB storage, $0.10 per hour, up to 32 GB RAM, 240 GB storage, $3.20 per hour); CDN and non-CDN bandwidth. Unusually, CDN is based on billing address, not the location where content is consumed. There is thus a simple scale of charges based on usage and location.



Windstream offer a wide range of enterprise-class cloud and managed services, enabling businesses build their own customised cloud solutions. Windstream provide cloud computing, storage and disaster recovery. Configurations include private and hybrid as well as public cloud, providing flexibility for businesses, and a migration service can be used to transfer data from existing physical and virtual machines onto Windstream’s cloud platform.

Windstream’s cloud solutions are built on a high-end, high-availability infrastructure, designed to scale rapidly to meet demands. They support multiple operating systems and are intended for applications that require high performance, security, scalability and availability; CRM, email, collaboration and non-mission critical applications; Production environments; Additional servers, storage, and backup infrastructure; and Applications testing, development and quality assurance.

Windstream’s storage boasts 99.9% uptime, and enables the control of data distribution through pre-defined storage policies. They operate a pay-as-you-use pricing model. Data storage criteria can be adapted at any time through a web service API, and additional storage can be rapidly deployed if necessary. The location of your data can also be specified, assisting you to meet performance criteria and regulatory compliance.

Windstream’s cloud migration service can be used to convert the customer’s Operating System, applications and data automatically into a virtualised server image. This is then deployed into the appropriate environment on the public cloud, with data being transferred over a secure, encrypted connection. The Migration Wizard can be used to migrate many servers at the same time, and scheduling allows the migration to be undertaken at off-peak times.


Google Cloud

Google is huge name on the web, and it’s well known for providing public cloud storage for individual users – with hundreds of millions of personal accounts for email, documents and general storage. The business solution is more wide-ranging, offering – as you might expect – a whole raft of tools for enterprises. It’s a household name with an established track record, so you know what you’re getting in terms of reliability. Whilst many companies provide public cloud access, there are few that do so with such a large and dedicated infrastructure, with multiple redundancies and backups to keep your data available whenever you need it. Not only that, but you’ll have access to Google’s innovations before the rest of the market – the new tools they create for business use.

Specialising in Infrastructure as a Service (IaaS), Google offers managed services – application, database and storage – to free you up to work on your product. It integrates well with popular development tools, and enables you to manage all of your applications from the same console. The pay-as-you-use service is highly scalable, as again you’d expect from a web giant, enabling you to reach millions of users or scale back down to a few hundred again, without paying for what you don’t need. There’s a mix-and-match approach to services, so you can pick exactly what you want without being lumbered with unnecessary elements – VMs, storage, databases, analytics and other services. Performance is fast and consistent, providing a reliable service to your end users. There’s also plenty of support, both through community-based resources and documentation, and 24/7 phone support in English or Japanese.



Fujitsu offer a series of cloud options: Trusted Public, Private Hosted, Private and hybrid. The company has a broad range of Infrastructure as a Service (IaaS) solutions, including computing services, storage as a service and data and application management.

Fujitsu’s basic public cloud offering is IaaS Trusted Public S5. This is designed from the ground up for business use, including ISO27001 security accreditation. Trusted Public S5 is delivered through a network of data centres located in Japan, Australia, United States of America, Singapore, United Kingdom and Germany. Cloud services include VMs, storage, networking, OS environment and middleware options.

VMs start at $0.125 per hour for an economy machine, up to $2.00 for a double high-performance service. Storage costs $0.00025 per GB per hour for all options. OS environments are typically charged monthly: $116 for Windows Server Enterprise Edition, $35.70 for Standard Edition, $300 for Redhat Enterprise Linux, with 24/7 support. Redhat can also be purchased for $0.1375 per hour, without support.

IaaS Trusted Public S5 Dedicated is an upgraded option that affords the same services but with the ability to use server, storage, and network environments reserved for your use. These may be either virtual or physical resources. The idea is that this makes IaaS Trusted Public S5 a viable solution for delivering your enterprise-ready production systems, whilst still making use of the economies of scale offered by the public cloud. IaaS Trusted Public S5 Dedicated opens the service to new customers, such as government and public sector bodies and financial services institutions. These would otherwise need private hosted or private cloud solutions in order to maintain the security and compliance required of them.



Internap’s cloud hosting service is designed for large-scale, performance-intensive workloads. It’s powered by OpenStack, a transparent and open source platform that is gaining popularity against the proprietary systems many other providers use. Internap’s AgileCLOUD is an Infrastructure as a Service (IaaS) platform that also offers off-the-peg hybrid hosting, allowing you to bridge the gap between the public and private cloud seamlessly and quickly.

Intended to be massively scalable and high-performance, AgileCLOUD enables interfacing with other OpenStack public and private clouds, as well as third party platforms. It offers high-performance SSD-based ephemeral and persistent storage, with administration and maintenance enabled through OpenStack’s APIs. You can mix and match virtual servers with bare-metal, colocation and hosting environment, according to need.

Pricing is in two tiers. Tier A offers shared compute cores, intended for moderate workloads such as small databases, websites and content management systems. Tier B options provide dedicated cores with a higher RAM-to-CPU ratio and SSD-based persistent storage with guaranteed IOPS, and are designed for higher workloads. Pricing varies for Linux and Windows. Tier A begins at $0.04 per hour for 1 vCPU, 1 GB RAM and 20 GB storage for Linux, up to $0.64 per hour for 16 vCPU, 16 GB RAM and 320 GB storage. Windows prices are twice as much.

Tier B only comes in Linux. 1 vCPU, 4 GB RAM and 20 GB storage costs $0.08 per hour, up to $1.28 for 16 vCPU, 60 GB RAM and 320 GB storage.


Microsoft (enterprise)

Another household name, Microsoft also provide personal storage and facilities for small business users through their OneDrive service, which is fully integrated with the Microsoft Office Suite in Windows 8 and up. Together with Microsoft Azure, Windows Server and Microsoft System Server, Microsoft’s public cloud can be used to span your own infrastructure to create a hybrid cloud. Office 365 integrates fully with the cloud to enable collaboration between employees regardless of their location, on industry-recognised and familiar software. Since millions of businesses already use Windows and Microsoft Office, it makes sense to extend its functionality using Microsoft’s cloud facilities. Social tools facilitate communication and team-building to share ideas, whilst Microsoft Dynamics CRM improves the customer experience. Further elements like analytics enable processing of data to discover insights that will benefit enterprise.



AT&T have a series of public cloud options, including storage, computing and networking – as well as a private cloud and virtual desktop service. They offer a pay-as-you-go, self-service model. The Synaptic Compute package has no set-up fees, and no usage commitments. You are charged for what you use, or can purchase a pool of resources. Unlike many other cloud providers, there is plenty of information on their website, meaning it is possible to gain a comprehensive picture without further material or customer support.

Virtual machines are charged on the basis of processing capacity, memory and system storage. Allocations are easy to change and if you no longer need the VM, you will only pay for storage. Prices are $0.030 per vCPU per hour for 1 to 12 vCPUs; $0.023 per GB per hour for 1 to 64 GB RAM; $0.10 per GB per month for up to 2 TB of system storage. Separate storage is an extra $0.15 per GB per month. Shared storage volumes (these can be accessed by multiple virtual machines) are $0.15 per GB per month for SAS drives, or $0.10 per GB per month for SATA. Data transfer is $0.10 per GB (Ipv4 or Ipv6).

AT&T provide a managed service at $195 per month per managed VM. This provides proactive monitoring, alerting and incident response for all applicable VMs. You can also purchase OS licences (Windows or Redhat) at $0.03 per vCPU per hour. For security, different customers’ data is partitioned and logically separated in dedicated file systems and database instances. Each customer’s data is transferred along a dedicated vLAN.


More about the public cloud

Depending on the model employed, the public cloud enables organisations and individuals to store documents cheaply and easily, and access them from any compatible device and platform. A document may be saved from a desktop computer in the office and accessed from a smartphone or tablet from home – or by another employee in the same company on the other side of the world.

The ability to store and retrieve data in this way, as well as the name ‘cloud’, has prompted a series of misconceptions about the public cloud. Even if these are not explicitly stated, the way we use the cloud often reflects these assumptions. We view the cloud as black box: a service into which we can throw our documents and collect them again at some point in the future without needing to know anything about what goes on after they leave our own devices.

In reality, this storage isn’t a diffuse cloud that lacks a presence in the real world. Storage has to take place on physical servers, housed in a data centre somewhere in the world. That data centre is located somewhere very specific. Although you might not know or care where it is, it’s in a particular country, and a particular legal jurisdiction. It has a particular set of employees, who have a given level of training and experience – although you’re unlikely to know that, either. The company has certain privacy policies, and commitments about uptime, and a track record in delivering on them or otherwise – as well as adhering to the requirements in their jurisdiction. The geography and climate of the area is relevant, since natural disasters and other issues could affect the integrity of your data.

All of these things can make a huge difference to the reliability of the service the ‘public cloud’ provides. Most of the popular cloud providers are multinational companies with data centres all over the world, who take backing up your data and maintaining security seriously. Nevertheless, we know from experience that problems can and do occur on a regular basis. Moreover, those companies themselves will have access to your data (unless it is client-side encrypted, as with Spideroak). In fact, it’s often part of their business model. Google will offer free storage in return to knowing your personal details and trawling through your content so that it can better understand you and serve you ads targeted to your profile.


Security of the public cloud

The great strength of the public cloud is its convenience. It’s possible simply to upload documents and forget about them until you need them, safe in the knowledge that they will be there when you come back for them. As we’ve discussed above, it’s a black box – people typically don’t know or care what goes on inside the public cloud, so long as they can access their files when they need to. A second benefit of the public cloud is cost: it’s far more cost-effective to use a free service or pay-per-use than it is to buy entire new hard drives or other storage yourself, and it’s less prone to hardware failure.

One key downside to the public cloud is its security. In some cases, the security of the services that cloud providers offer is excellent. In other cases, data is leaked, stolen, lost or damaged. The critical factor here is that when you use the public cloud, you are handing over control of your data to someone one. You are dependent on the competence and policies of a third party for your security. The nature of the public cloud means there is frequently a lack of visibility around that. Whilst many people use the cloud without issue, there have been a series of major new stories about hacks, outages and other problems to do with most of the big cloud providers.

Apple has been the subject of several hacks and attempted hacks, the most infamous of which was the theft of a large number of explicit images saved to the cloud by celebrities. There is evidence that Apple had been informed of the security loophole six months before this occurred. Apple claimed that the hackers were able to gain access through the common practice of guessing names, passwords and answers to security questions, which had not been set properly – enabling the hackers to determine them relatively easily. At the beginning of 2015, a new exploit was published on the web, allowing anyone who downloaded a hacking tool to access iCloud accounts ‘protected’ by common passwords through a simple brute-force attack. In this instance, Apple acted quickly to patch the hole, but the episode was a reminder that even the biggest tech companies are not infallible.

Dropbox’s users have also been the victim of various hacks and thefts. In 2014 files containing millions of user passwords were leaked and offered online. These were encrypted, but hundreds of usernames and passwords were given in plain text as a taster; the hacker posted them to a well-known site and offered to sell the remaining names in return for bitcoins. Dropbox stated that they had not been stolen from its servers, but from third party services. In reality, it seems that the usernames and passwords had been taken from elsewhere, and the hackers had tried them on numerous different sites – including Dropbox – because people tend to reuse the same passwords for simplicity. Although this incident may not have directly been Dropbox’s fault, there have been others. In 2011, a faulty software update enabled users to access other people’s accounts without a password for a period of some hours. In 2012 another data breach resulted in customers receiving spam email.

Business social network LinkedIn was less careful, and has been responsible for serious issues involving its users’ passwords. In 2012 the website was hacked by Russian criminals, resulting in the release of 6.5 million passwords. These were promptly decrypted from the format in which they were kept by LinkedIn and posted in plain text on the internet. Compromised users were not able to access their accounts and were encouraged to change their passwords.

These are just some of the many incidents that demonstrate the security issues of the public cloud. Alongside the convenience and cost benefits of the cloud there is the potential for a serious security breach. Whilst individual users may ignore these for casual storage of images and documents, for businesses there are more serious implications – both in terms of the legal ramifications, and in terms of the business itself if critical information is stolen. For this reason, businesses with sensitive data will often opt for local storage, a private cloud (either on their own premises or in a secure data centre), or for a hybrid cloud that enables them to keep key data securely and less critical information in the public cloud to reduce costs.



The public cloud has various advantages and disadvantages. These will become more or less important depending on factors including the level of storage required, the nature of the individual or organisation’s requirements, the type of organisation, regulatory issues and more. Most of the problems can be mitigated in some way, though often at the cost of usability or higher fees.

Advantages of the public cloud

  • Cost. Users require no additional hardware to store their documents on the public cloud, meaning they need minimal local storage. The first 5-15 GB of storage is typically free, and further storage can be purchased extremely cheaply – 20 GB typically costs just $0.99 per month. There is no upper limit for the amount of storage that can be purchased.
  • Scalability. Because cloud providers have huge data centres across the world, it is easy to scale storage quickly and cost-effectively. Customers can adopt a pay-per-use approach in which they are only charged for the space they need. This is in contrast to purchasing their own new hardware, leaving most of the available storage empty to begin with and then needing to purchase an expensive new drive when it fills up.
  • Convenience. The ‘black box’ approach means that users simply save their data to the cloud and access it when they need it. They do not generally need to worry about what happens in between – all of the maintenance arrangements are taken care of by the cloud provider.
  • Reliability. When organisations have their own local storage, it may be subject to outages and damage from environmental factors. Backups should regularly be taken, which can be extremely time-consuming. Cloud providers typically back up their data at regular intervals, and – barring rare outages – the cloud should be available at all times.
  • Accessibility. Unlike a server on a private network or a local hard drive, it is straightforward to access data on the public cloud from any device, and any location with an internet connection. This makes working from home, travelling for work and collaborating on projects far easier.

Disadvantages of the public cloud

  • Use of the public cloud involves trusting a third party with your data. Although most of the time there will not be a problem, the reality is that data loss can and does occur. Data can be lost through corruption or deletion or, more concerningly, may be acquired by hackers. It is therefore advisable not to store any valuable or sensitive data on the public cloud unless it is encrypted.
  • Open-ended costs. The advantage of public cloud storage is that it expands to meet an organisation’s or individual’s needs, on a pay-per-use basis. The disadvantage of this is that it is easy to keep increasing your cloud storage use, incurring greater costs, because the unlimited space means there is no incentive for best practice. Large and inefficient files may be saved without being optimised, and old files that are no longer needed may be kept unnecessarily. Losing track of how much storage you really need means you could be paying a lot more than you need to.
  • Speed and reliability. Your only link to the public cloud is through your internet connection. Any file you upload or download is limited by your available bandwidth – and if there are restrictions on data usage, they will count towards your total. With a private cloud or local hard drive, your access to your data is not determined by the state of the network, which may be provided by a separate company. If your connection is slow or prone to outages, you can be cut off from your data – sometimes for hours or even days. For some organisations, this poses an unacceptable risk.
  • Opacity. The public cloud is run by an organisation other than your own. Even if you have read its terms and conditions, much of what it does will be completely opaque to you – and you have no visibility over whether its policies are properly and competently followed, or whether its employees have been adequately security checked.



The public cloud represents a convenient and cost-effective solution for a wide range of storage needs. It is best used for personal data and non-sensitive information, because its biggest drawback is the potential security risks. For large amounts of data or if you have a slow internet connection, speed of access may also be an issue.

For larger organisations and those dealing with critical data, the public cloud is less suitable. There are ways around the security vulnerabilities, for example by using client-side encryption before uploading files. However, one of the benefits of the public cloud is the apps that different providers tend to bundle with their offerings, including Google Drive’s office apps and OneDrive’s integration with the Microsoft Office suite. These make accessing documents from any device straightforward, and enable easy collaboration with other users around the world. Such facilities rely on data being unencrypted, though.

You can also use applications that monitor the use of cloud storage within an organisation, so it is possible to learn which employees are using what functionality. You can control what areas of your public cloud storage may be accessed from different devices. This is important because many employees bring their own devices into work and use them to access work documents. They also access work material from home and use office computers for personal reasons, too. All of this creates a far more porous system in which it is hard to track data and manage vulnerabilities.

If your organisation deals with any amount of sensitive data, though, a different solution will be preferable. A private cloud eliminates the risks of handing your data over to a third party, but comes with greater expenses and maintenance requirements. A hybrid cloud allows the best of both worlds, by enabling you to save critical data locally on your secure server, and taking advantage of the economies of scale offered by the public cloud for large amounts of less sensitive material.

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