The browser-based BlockSim alternative
ReliaSoft BlockSim is a deep, established desktop tool. Ramly answers the core RAM question — what availability does this system achieve, and where is the downtime coming from? — in your browser, with nothing to install and no purchase order.
ReliaSoft BlockSim is one of the most established names in system reliability: a Windows desktop application that models reliability block diagrams — and fault trees, and Markov chains — as part of the broader ReliaSoft reliability suite. It is a mature, wide-ranging tool with a long track record.
Ramly makes a narrower, different bet: do the RBD RAM study extremely well, in the browser, with no install and no procurement cycle. Like BlockSim, it offers both Monte Carlo simulation and an exact analytical (Markov/CTMC) solver— so you can get an instant closed-form answer or simulate full maintenance logistics. If your question is “what availability does this design achieve, and which equipment drives the downtime?”, Ramly answers it in minutes from any machine. Where BlockSim still goes further is fault trees, reliability phase diagrams and the wider ReliaSoft suite.
Feature comparison
| Ramly | ReliaSoft BlockSim | |
|---|---|---|
| Deployment | Runs in any modern browser — nothing to install, on macOS, Windows or Linux. | Windows desktop application, installed per machine. |
| Getting started | Sign up and open a worked example model in minutes. | Per-seat license, typically quoted and procured, then installed by IT. |
| Core method | Reliability block diagrams, evaluated both by discrete-event Monte Carlo simulation and by an exact analytical (Markov/CTMC) solver. | Reliability block diagrams, evaluated both analytically and by simulation. |
| Distributions | Exponential, Weibull, normal, lognormal, uniform, triangular, constant. | Broad distribution library. |
| Redundancy & standby | k-of-n parallel; cold/warm standby with a separate dormant failure rate. | k-of-n, standby and load-sharing configurations. |
| Maintenance realism | Preventive maintenance, logistics delay, shared repair crews with queuing, and spare pools with stock-out tracking. | Crews, spares and maintenance tasks via its resource model. |
| Common-cause failures | Beta-factor CCF groups. | Supported. |
| Hidden failures & proof testing | Dormant failures revealed by inspection or on demand; per-component or per-mode; reports mean time undetected and PFDavg. | Hidden/dormant failures, inspection tasks and PFD via its maintenance & FMEDA tooling. |
| Production / throughput | Real-unit throughput capacity → production availability and lost production in t/h, not just a percentage. | Throughput / flow throughput analysis available. |
| Importance & sensitivity | Birnbaum, RAW and RRW importance, plus ±20% MTTF/MTTR sensitivity. | Reliability importance measures. |
| Analytical & Markov solver | Exact closed-form RBD algebra plus Markov (CTMC) for standby, common-cause and multi-state — with time-dependent availability A(t), reliability R(t) and MTTF. | Analytical and Markov solution methods included. |
| Multi-state / partial capacity | Multi-state components with per-state capacity, solved analytically for production availability. | Supported. |
| Fault tree & phase diagrams | Not offered — Ramly is RBD-focused. | Fault tree and reliability phase diagrams included. |
| Wider reliability suite | A single focused tool. | Part of the broader ReliaSoft / Synthesis platform (Weibull++ life data, Xfmea, prediction). |
| Automation | Python API (libram.so) for scripted, repeatable runs. | Automation via its platform APIs. |
| Reproducibility | Fix the random seed and any reviewer re-runs to an identical result. | Seedable simulation. |
| Pricing | Subscription, published pricing — below most corporate card thresholds. | Per-seat license, quote-based. |
Which one should you use?
Choose Ramly when…
- ▸You want to start a study today — no install, no purchase order, any operating system.
- ▸Your team is on mixed OSes or simply works from the browser.
- ▸You need operational and production availability with realistic maintenance, spares and crews.
- ▸You value reproducible seeded runs and a scriptable Python API.
- ▸A subscription fits your budget better than a per-seat capital license.
Choose BlockSim when…
- ▸You need fault tree analysis or reliability phase diagrams alongside RBD.
- ▸You rely on the wider ReliaSoft suite — Weibull++ life-data, Xfmea/FMECA, prediction.
- ▸Your organisation standardises on an established desktop tool with a long validation history.
Try a real RAM study in your browser
No install, no procurement. Open a worked example model, run a Monte Carlo simulation and read the availability results in minutes.
Comparison reflects ReliaSoft BlockSim’s publicly published materials as of June 2026 and has not been independently benchmarked. ReliaSoft BlockSim and all other product names are trademarks of their respective owners and are used here only for identification and comparison. Capabilities and licensing of third-party products change — verify current details with the vendor.